20981275776 has 160 divisors (see below), whose sum is σ = 62538024780. Its totient is φ = 6982778880.

The previous prime is 20981275771. The next prime is 20981275813. The reversal of 20981275776 is 67757218902.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20220840000 + 760435776 = 142200^2 + 27576^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20981275771) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 9133060 + ... + 9135356.

Almost surely, 2^20981275776 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 20981275776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31269012390).

20981275776 is an abundant number, since it is smaller than the sum of its proper divisors (41556749004).

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

20981275776 is an equidigital number, since it uses as much as digits as its factorization.

20981275776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3204 (or 3183 counting only the distinct ones).

The product of its (nonzero) digits is 2963520, while the sum is 54.

The spelling of 20981275776 in words is "twenty billion, nine hundred eighty-one million, two hundred seventy-five thousand, seven hundred seventy-six".