2156551660 has 48 divisors (see below), whose sum is σ = 4924783584. Its totient is φ = 789931008.

The previous prime is 2156551591. The next prime is 2156551687. The reversal of 2156551660 is 661556512.

It is a Harshad number since it is a multiple of its sum of digits (37).

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, 73134 + ... + 98293.

It is an arithmetic number, because the mean of its divisors is an integer number (102599658).

Almost surely, 2^2156551660 is an apocalyptic number.

2156551660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2156551660 is an abundant number, since it is smaller than the sum of its proper divisors (2768231924).

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

2156551660 is a wasteful number, since it uses less digits than its factorization.

2156551660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171490 (or 171488 counting only the distinct ones).

The product of its (nonzero) digits is 54000, while the sum is 37.

The square root of 2156551660 is about 46438.6871046114. The cubic root of 2156551660 is about 1291.9725565840.

The spelling of 2156551660 in words is "two billion, one hundred fifty-six million, five hundred fifty-one thousand, six hundred sixty".