20657557660 has 24 divisors (see below), whose sum is σ = 43479707040. Its totient is φ = 8244197184.

The previous prime is 20657557643. The next prime is 20657557691. The reversal of 20657557660 is 6675575602.

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, 1167619 + ... + 1185178.

It is an arithmetic number, because the mean of its divisors is an integer number (1811654460).

Almost surely, 2^20657557660 is an apocalyptic number.

20657557660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20657557660 is an abundant number, since it is smaller than the sum of its proper divisors (22822149380).

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

20657557660 is a wasteful number, since it uses less digits than its factorization.

20657557660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2353245 (or 2353243 counting only the distinct ones).

The product of its (nonzero) digits is 2646000, while the sum is 49.

The spelling of 20657557660 in words is "twenty billion, six hundred fifty-seven million, five hundred fifty-seven thousand, six hundred sixty".