812992558921 has 9 divisors (see below), whose sum is σ = 815188600821. Its totient is φ = 810802424352.

The previous prime is 812992558877. The next prime is 812992558943. The reversal of 812992558921 is 129855299218.

The square root of 812992558921 is 901661.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 9065134521 + 803927424400 = 95211^2 + 896620^2 .

It is not a de Polignac number, because 812992558921 - 2²¹ = 812990461769 is a prime.

It is a Duffinian number.

Its product of digits (9331200) is a multiple of the sum of its prime divisors (2430).

It is a self number, because there is not a number n which added to its sum of digits gives 812992558921.

It is not an unprimeable number, because it can be changed into a prime (812992558981) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 412058091 + ... + 412060063.

Almost surely, 2^812992558921 is an apocalyptic number.

812992558921 is the 901661-st square number.

812992558921 is the 450831-st centered octagonal number.

It is an amenable number.

812992558921 is a deficient number, since it is larger than the sum of its proper divisors (2196041900).

812992558921 is an frugal number, since it uses more digits than its factorization.

812992558921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4860 (or 2430 counting only the distinct ones).

The product of its digits is 9331200, while the sum is 61.

The spelling of 812992558921 in words is "eight hundred twelve billion, nine hundred ninety-two million, five hundred fifty-eight thousand, nine hundred twenty-one".