21011595264 has 512 divisors, whose sum is σ = 72476467200. Its totient is φ = 5945425920.

The previous prime is 21011595263. The next prime is 21011595271. The reversal of 21011595264 is 46259511012.

21011595264 is a `hidden beast` number, since 2 + 1 + 0 + 1 + 1 + 595 + 2 + 64 = 666.

It is a tau number, because it is divible by the number of its divisors (512).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011595263) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 165445569 + ... + 165445695.

It is an arithmetic number, because the mean of its divisors is an integer number (141555600).

Almost surely, 2^21011595264 is an apocalyptic number.

21011595264 is a gapful number since it is divisible by the number (24) 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 21011595264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36238233600).

21011595264 is an abundant number, since it is smaller than the sum of its proper divisors (51464871936).

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

21011595264 is a wasteful number, since it uses less digits than its factorization.

21011595264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194 (or 160 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 36.

The spelling of 21011595264 in words is "twenty-one billion, eleven million, five hundred ninety-five thousand, two hundred sixty-four".