20779681920 has 128 divisors (see below), whose sum is σ = 68372052480. Its totient is φ = 5362483200.

The previous prime is 20779681891. The next prime is 20779681933. The reversal of 20779681920 is 2918697702.

It is a tau number, because it is divible by the number of its divisors (128).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 115041 + ... + 234080.

It is an arithmetic number, because the mean of its divisors is an integer number (534156660).

Almost surely, 2^20779681920 is an apocalyptic number.

20779681920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20779681920 is an abundant number, since it is smaller than the sum of its proper divisors (47592370560).

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

20779681920 is a wasteful number, since it uses less digits than its factorization.

20779681920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 349174 (or 349162 counting only the distinct ones).

The product of its (nonzero) digits is 762048, while the sum is 51.

The spelling of 20779681920 in words is "twenty billion, seven hundred seventy-nine million, six hundred eighty-one thousand, nine hundred twenty".