2155138668 has 36 divisors (see below), whose sum is σ = 5467403760. Its totient is φ = 715782816.

The previous prime is 2155138633. The next prime is 2155138697. The reversal of 2155138668 is 8668315512.

2155138668 is a `hidden beast` number, since 2 + 1 + 551 + 38 + 6 + 68 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 98088 + ... + 118031.

Almost surely, 2^2155138668 is an apocalyptic number.

It is an amenable number.

2155138668 is an abundant number, since it is smaller than the sum of its proper divisors (3312265092).

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

2155138668 is a wasteful number, since it uses less digits than its factorization.

2155138668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216406 (or 216401 counting only the distinct ones).

The product of its digits is 345600, while the sum is 45.

The square root of 2155138668 is about 46423.4710895254. The cubic root of 2155138668 is about 1291.6903242637.

The spelling of 2155138668 in words is "two billion, one hundred fifty-five million, one hundred thirty-eight thousand, six hundred sixty-eight".