21320510456 has 64 divisors (see below), whose sum is σ = 46612800000. Its totient is φ = 8953176960.

The previous prime is 21320510447. The next prime is 21320510467. The reversal of 21320510456 is 65401502312.

It is a super-2 number, since 2×21320510456² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

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, 1017170 + ... + 1037918.

It is an arithmetic number, because the mean of its divisors is an integer number (728325000).

Almost surely, 2^21320510456 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 21320510456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23306400000).

21320510456 is an abundant number, since it is smaller than the sum of its proper divisors (25292289544).

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

21320510456 is a wasteful number, since it uses less digits than its factorization.

21320510456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21132 (or 21128 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 29.

The spelling of 21320510456 in words is "twenty-one billion, three hundred twenty million, five hundred ten thousand, four hundred fifty-six".