2187161864 has 8 divisors (see below), whose sum is σ = 4100928510. Its totient is φ = 1093580928.

The previous prime is 2187161849. The next prime is 2187161909. The reversal of 2187161864 is 4681617812.

It can be written as a sum of positive squares in only one way, i.e., 1132860964 + 1054300900 = 33658^2 + 32470^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 136697609 + ... + 136697624.

Almost surely, 2^2187161864 is an apocalyptic number.

It is an amenable number.

2187161864 is a deficient number, since it is larger than the sum of its proper divisors (1913766646).

2187161864 is a wasteful number, since it uses less digits than its factorization.

2187161864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273395239 (or 273395235 counting only the distinct ones).

The product of its digits is 129024, while the sum is 44.

The square root of 2187161864 is about 46767.1023690799. The cubic root of 2187161864 is about 1298.0566355710.

The spelling of 2187161864 in words is "two billion, one hundred eighty-seven million, one hundred sixty-one thousand, eight hundred sixty-four".