21715802520 has 64 divisors (see below), whose sum is σ = 66736383840. Its totient is φ = 5649638400.

The previous prime is 21715802513. The next prime is 21715802527. The reversal of 21715802520 is 2520851712.

It is an interprime number because it is at equal distance from previous prime (21715802513) and next prime (21715802527).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21715802527) by changing a digit.

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, 2201971 + ... + 2211810.

Almost surely, 2^21715802520 is an apocalyptic number.

21715802520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21715802520 is an abundant number, since it is smaller than the sum of its proper divisors (45020581320).

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

21715802520 is a wasteful number, since it uses less digits than its factorization.

21715802520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4413836 (or 4413832 counting only the distinct ones).

The product of its (nonzero) digits is 11200, while the sum is 33.

The spelling of 21715802520 in words is "twenty-one billion, seven hundred fifteen million, eight hundred two thousand, five hundred twenty".