2156481640 has 32 divisors (see below), whose sum is σ = 4877241480. Its totient is φ = 858120192.

The previous prime is 2156481599. The next prime is 2156481697. The reversal of 2156481640 is 461846512.

It can be written as a sum of positive squares in 4 ways, for example, as 1920367684 + 236113956 = 43822^2 + 15366^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 2156481640.

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, 131949 + ... + 147388.

Almost surely, 2^2156481640 is an apocalyptic number.

2156481640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2156481640 is an abundant number, since it is smaller than the sum of its proper divisors (2720759840).

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

2156481640 is a wasteful number, since it uses less digits than its factorization.

2156481640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279541 (or 279537 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 37.

The square root of 2156481640 is about 46437.9332012095. The cubic root of 2156481640 is about 1291.9585736285.

The spelling of 2156481640 in words is "two billion, one hundred fifty-six million, four hundred eighty-one thousand, six hundred forty".