2157881688 has 32 divisors (see below), whose sum is σ = 5994116400. Its totient is φ = 719293824.

The previous prime is 2157881683. The next prime is 2157881711. The reversal of 2157881688 is 8861887512.

2157881688 is a `hidden beast` number, since 2 + 1 + 578 + 8 + 1 + 68 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2157881683) by changing a digit.

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, 4994881 + ... + 4995312.

Almost surely, 2^2157881688 is an apocalyptic number.

It is an amenable number.

2157881688 is an abundant number, since it is smaller than the sum of its proper divisors (3836234712).

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

2157881688 is a wasteful number, since it uses less digits than its factorization.

2157881688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9990208 (or 9990198 counting only the distinct ones).

The product of its digits is 1720320, while the sum is 54.

The square root of 2157881688 is about 46453.0051557485. The cubic root of 2157881688 is about 1292.2381049853.

The spelling of 2157881688 in words is "two billion, one hundred fifty-seven million, eight hundred eighty-one thousand, six hundred eighty-eight".