861922521 has 6 divisors (see below), whose sum is σ = 1244999210. Its totient is φ = 574615008.

The previous prime is 861922499. The next prime is 861922549. The reversal of 861922521 is 125229168.

It can be written as a sum of positive squares in only one way, i.e., 480267225 + 381655296 = 21915^2 + 19536^2 .

It is not a de Polignac number, because 861922521 - 2⁷ = 861922393 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (861922591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 47884576 + ... + 47884593.

Almost surely, 2^861922521 is an apocalyptic number.

It is an amenable number.

861922521 is a deficient number, since it is larger than the sum of its proper divisors (383076689).

861922521 is a wasteful number, since it uses less digits than its factorization.

861922521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95769175 (or 95769172 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 861922521 is about 29358.5170095494. The cubic root of 861922521 is about 951.6766406588.

The spelling of 861922521 in words is "eight hundred sixty-one million, nine hundred twenty-two thousand, five hundred twenty-one".