21256317962208 has 216 divisors, whose sum is σ = 70341524999928. Its totient is φ = 6071086038528.

The previous prime is 21256317962071. The next prime is 21256317962239. The reversal of 21256317962208 is 80226971365212.

21256317962208 is a `hidden beast` number, since 2 + 1 + 2 + 5 + 6 + 3 + 1 + 7 + 9 + 622 + 0 + 8 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 39855510 + ... + 40385322.

It is an arithmetic number, because the mean of its divisors is an integer number (325655208333).

Almost surely, 2^{21256317962208} is an apocalyptic number.

21256317962208 is a gapful number since it is divisible by the number (28) 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 21256317962208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35170762499964).

21256317962208 is an abundant number, since it is smaller than the sum of its proper divisors (49085207037720).

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

21256317962208 is a wasteful number, since it uses less digits than its factorization.

21256317962208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 532686 (or 532668 counting only the distinct ones).

The product of its (nonzero) digits is 4354560, while the sum is 54.

The spelling of 21256317962208 in words is "twenty-one trillion, two hundred fifty-six billion, three hundred seventeen million, nine hundred sixty-two thousand, two hundred eight".