21656193508512 has 192 divisors, whose sum is σ = 63626605660800. Its totient is φ = 7166026506240.

The previous prime is 21656193508471. The next prime is 21656193508559. The reversal of 21656193508512 is 21580539165612.

21656193508512 is a `hidden beast` number, since 2 + 1 + 6 + 5 + 619 + 3 + 5 + 0 + 8 + 5 + 12 = 666.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

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, 70763568 + ... + 71068944.

It is an arithmetic number, because the mean of its divisors is an integer number (331388571150).

Almost surely, 2^{21656193508512} 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 21656193508512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31813302830400).

21656193508512 is an abundant number, since it is smaller than the sum of its proper divisors (41970412152288).

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

21656193508512 is a wasteful number, since it uses less digits than its factorization.

21656193508512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305996 (or 305982 counting only the distinct ones).

The product of its (nonzero) digits is 3888000, while the sum is 54.

The spelling of 21656193508512 in words is "twenty-one trillion, six hundred fifty-six billion, one hundred ninety-three million, five hundred eight thousand, five hundred twelve".