20978857747968 has 80 divisors (see below), whose sum is σ = 56259114590976. Its totient is φ = 6946641561600.

The previous prime is 20978857747931. The next prime is 20978857748003. The reversal of 20978857747968 is 86974775887902.

It is a super-2 number, since 2×20978857747968² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44993596 + ... + 45457467.

Almost surely, 2^{20978857747968} is an apocalyptic number.

It is an amenable number.

20978857747968 is an abundant number, since it is smaller than the sum of its proper divisors (35280256843008).

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

20978857747968 is an equidigital number, since it uses as much as digits as its factorization.

20978857747968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90451235 (or 90451219 counting only the distinct ones).

The product of its (nonzero) digits is 23897825280, while the sum is 87.

The spelling of 20978857747968 in words is "twenty trillion, nine hundred seventy-eight billion, eight hundred fifty-seven million, seven hundred forty-seven thousand, nine hundred sixty-eight".