861972158 has 16 divisors (see below), whose sum is σ = 1301650560. Its totient is φ = 428097696.

The previous prime is 861972157. The next prime is 861972169. The reversal of 861972158 is 851279168.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861972157) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 225116 + ... + 228912.

It is an arithmetic number, because the mean of its divisors is an integer number (81353160).

Almost surely, 2^861972158 is an apocalyptic number.

861972158 is a deficient number, since it is larger than the sum of its proper divisors (439678402).

861972158 is a wasteful number, since it uses less digits than its factorization.

861972158 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4531.

The product of its digits is 241920, while the sum is 47.

The square root of 861972158 is about 29359.3623568360. The cubic root of 861972158 is about 951.6949089159.

The spelling of 861972158 in words is "eight hundred sixty-one million, nine hundred seventy-two thousand, one hundred fifty-eight".