861809472 has 84 divisors (see below), whose sum is σ = 2555450820. Its totient is φ = 277358592.

The previous prime is 861809423. The next prime is 861809503. The reversal of 861809472 is 274908168.

It can be written as a sum of positive squares in 2 ways, for example, as 721244736 + 140564736 = 26856^2 + 11856^2 .

It is a congruent 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, 9093 + ... + 42500.

Almost surely, 2^861809472 is an apocalyptic number.

It is an amenable number.

861809472 is an abundant number, since it is smaller than the sum of its proper divisors (1693641348).

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

861809472 is a wasteful number, since it uses less digits than its factorization.

861809472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51640 (or 51627 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The square root of 861809472 is about 29356.5916277759. The cubic root of 861809472 is about 951.6350318158.

The spelling of 861809472 in words is "eight hundred sixty-one million, eight hundred nine thousand, four hundred seventy-two".