2151705987 has 24 divisors (see below), whose sum is σ = 3174799680. Its totient is φ = 1403866800.

The previous prime is 2151705979. The next prime is 2151705991. The reversal of 2151705987 is 7895071512.

2151705987 is a `hidden beast` number, since 2 + 1 + 51 + 7 + 0 + 598 + 7 = 666.

It is not a de Polignac number, because 2151705987 - 2³ = 2151705979 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2151705937) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 111612 + ... + 129462.

It is an arithmetic number, because the mean of its divisors is an integer number (132283320).

Almost surely, 2^2151705987 is an apocalyptic number.

2151705987 is a deficient number, since it is larger than the sum of its proper divisors (1023093693).

2151705987 is a wasteful number, since it uses less digits than its factorization.

2151705987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18143 (or 18140 counting only the distinct ones).

The product of its (nonzero) digits is 176400, while the sum is 45.

The square root of 2151705987 is about 46386.4849606003. The cubic root of 2151705987 is about 1291.0041631508.

The spelling of 2151705987 in words is "two billion, one hundred fifty-one million, seven hundred five thousand, nine hundred eighty-seven".