20976979968 has 520 divisors, whose sum is σ = 73417571200. Its totient is φ = 5917556736.

The previous prime is 20976979957. The next prime is 20976979979. The reversal of 20976979968 is 86997967902.

It is an interprime number because it is at equal distance from previous prime (20976979957) and next prime (20976979979).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 20976979896 and 20976979905.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 265531353 + ... + 265531431.

Almost surely, 2^20976979968 is an apocalyptic number.

20976979968 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 20976979968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36708785600).

20976979968 is an abundant number, since it is smaller than the sum of its proper divisors (52440591232).

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

20976979968 is an frugal number, since it uses more digits than its factorization.

20976979968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140 (or 91 counting only the distinct ones).

The product of its (nonzero) digits is 185177664, while the sum is 72.

The spelling of 20976979968 in words is "twenty billion, nine hundred seventy-six million, nine hundred seventy-nine thousand, nine hundred sixty-eight".