20981776960 has 56 divisors (see below), whose sum is σ = 50082419520. Its totient is φ = 8372626944.

The previous prime is 20981776957. The next prime is 20981776973. The reversal of 20981776960 is 6967718902.

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, 55837 + ... + 212323.

It is an arithmetic number, because the mean of its divisors is an integer number (894328920).

Almost surely, 2^20981776960 is an apocalyptic number.

20981776960 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 20981776960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25041209760).

20981776960 is an abundant number, since it is smaller than the sum of its proper divisors (29100642560).

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

20981776960 is a wasteful number, since it uses less digits than its factorization.

20981776960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156923 (or 156913 counting only the distinct ones).

The product of its (nonzero) digits is 2286144, while the sum is 55.

The spelling of 20981776960 in words is "twenty billion, nine hundred eighty-one million, seven hundred seventy-six thousand, nine hundred sixty".