21904598640 has 80 divisors (see below), whose sum is σ = 68245632000. Its totient is φ = 5811860736.

The previous prime is 21904598627. The next prime is 21904598659. The reversal of 21904598640 is 4689540912.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×21904598640² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 21904598640.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 181560 + ... + 277079.

It is an arithmetic number, because the mean of its divisors is an integer number (853070400).

Almost surely, 2^21904598640 is an apocalyptic number.

21904598640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21904598640 is an abundant number, since it is smaller than the sum of its proper divisors (46341033360).

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

21904598640 is a wasteful number, since it uses less digits than its factorization.

21904598640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 458854 (or 458848 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 48.

The spelling of 21904598640 in words is "twenty-one billion, nine hundred four million, five hundred ninety-eight thousand, six hundred forty".