21203213864 has 64 divisors (see below), whose sum is σ = 46177689600. Its totient is φ = 8939577024.

The previous prime is 21203213813. The next prime is 21203213879. The reversal of 21203213864 is 46831230212.

It is a self number, because there is not a number n which added to its sum of digits gives 21203213864.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1101329 + ... + 1120415.

It is an arithmetic number, because the mean of its divisors is an integer number (721526400).

Almost surely, 2^21203213864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21203213864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23088844800).

21203213864 is an abundant number, since it is smaller than the sum of its proper divisors (24974475736).

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

21203213864 is a wasteful number, since it uses less digits than its factorization.

21203213864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19422 (or 19418 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 32.

The spelling of 21203213864 in words is "twenty-one billion, two hundred three million, two hundred thirteen thousand, eight hundred sixty-four".