21264695520 has 192 divisors, whose sum is σ = 69678766080. Its totient is φ = 5445273600.

The previous prime is 21264695509. The next prime is 21264695539. The reversal of 21264695520 is 2559646212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1943826 + ... + 1954734.

It is an arithmetic number, because the mean of its divisors is an integer number (362910240).

Almost surely, 2^21264695520 is an apocalyptic number.

21264695520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21264695520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34839383040).

21264695520 is an abundant number, since it is smaller than the sum of its proper divisors (48414070560).

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

21264695520 is a wasteful number, since it uses less digits than its factorization.

21264695520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11089 (or 11081 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 42.

The spelling of 21264695520 in words is "twenty-one billion, two hundred sixty-four million, six hundred ninety-five thousand, five hundred twenty".