20951981568000 has 2496 divisors, whose sum is σ = 96255452666880. Its totient is φ = 4267966464000.

The previous prime is 20951981567987. The next prime is 20951981568041. The reversal of 20951981568000 is 86518915902.

20951981568000 is a `hidden beast` number, since 20 + 9 + 51 + 9 + 8 + 1 + 568 + 0 + 0 + 0 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 10418686995 + ... + 10418689005.

It is an arithmetic number, because the mean of its divisors is an integer number (38563883280).

Almost surely, 2^{20951981568000} is an apocalyptic number.

20951981568000 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 20951981568000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48127726333440).

20951981568000 is an abundant number, since it is smaller than the sum of its proper divisors (75303471098880).

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

20951981568000 is a wasteful number, since it uses less digits than its factorization.

20951981568000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2099 (or 2064 counting only the distinct ones).

The product of its (nonzero) digits is 1555200, while the sum is 54.

The spelling of 20951981568000 in words is "twenty trillion, nine hundred fifty-one billion, nine hundred eighty-one million, five hundred sixty-eight thousand".