861989994 has 24 divisors (see below), whose sum is σ = 1872949572. Its totient is φ = 286513920.

The previous prime is 861989971. The next prime is 861990029. The reversal of 861989994 is 499989168.

861989994 is a `hidden beast` number, since 8 + 619 + 8 + 9 + 9 + 9 + 4 = 666.

861989994 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 811395225 + 50594769 = 28485^2 + 7113^2 .

It is a super-2 number, since 2×861989994² = 1486053499512240072, which contains 22 as substring.

It is a Curzon number.

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, 61477 + ... + 74184.

Almost surely, 2^861989994 is an apocalyptic number.

861989994 is an abundant number, since it is smaller than the sum of its proper divisors (1010959578).

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

861989994 is a wasteful number, since it uses less digits than its factorization.

861989994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136022 (or 136019 counting only the distinct ones).

The product of its digits is 10077696, while the sum is 63.

The square root of 861989994 is about 29359.6661084557. Note that the first 3 decimals coincide. The cubic root of 861989994 is about 951.7014730542.

The spelling of 861989994 in words is "eight hundred sixty-one million, nine hundred eighty-nine thousand, nine hundred ninety-four".