9999864 has 48 divisors (see below), whose sum is σ = 30953520. Its totient is φ = 2856960.

The previous prime is 9999863. The next prime is 9999877. The reversal of 9999864 is 4689999.

It is a happy number.

9999864 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a nude number because it is divisible by every one of its digits.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 9999864.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9999863) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9417 + ... + 10424.

It is an arithmetic number, because the mean of its divisors is an integer number (644865).

Almost surely, 2^9999864 is an apocalyptic number.

It is an amenable number.

9999864 is an abundant number, since it is smaller than the sum of its proper divisors (20953656).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

9999864 is a wasteful number, since it uses less digits than its factorization.

9999864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19860 (or 19853 counting only the distinct ones).

The product of its digits is 1259712, while the sum is 54.

The square root of 9999864 is about 3162.2561566072. The cubic root of 9999864 is about 215.4424923217.

The spelling of 9999864 in words is "nine million, nine hundred ninety-nine thousand, eight hundred sixty-four".