2157664660 has 24 divisors (see below), whose sum is σ = 4535709696. Its totient is φ = 862187040.

The previous prime is 2157664627. The next prime is 2157664727. The reversal of 2157664660 is 664667512.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34612 + ... + 74251.

It is an arithmetic number, because the mean of its divisors is an integer number (188987904).

Almost surely, 2^2157664660 is an apocalyptic number.

2157664660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2157664660 is an abundant number, since it is smaller than the sum of its proper divisors (2378045036).

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

2157664660 is a wasteful number, since it uses less digits than its factorization.

2157664660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109863 (or 109861 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 43.

The square root of 2157664660 is about 46450.6691017471. The cubic root of 2157664660 is about 1292.1947814402.

The spelling of 2157664660 in words is "two billion, one hundred fifty-seven million, six hundred sixty-four thousand, six hundred sixty".