812721531 has 8 divisors (see below), whose sum is σ = 1083856720. Its totient is φ = 541700352.

The previous prime is 812721529. The next prime is 812721563. The reversal of 812721531 is 135127218.

812721531 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 812721531 - 2¹ = 812721529 is a prime.

It is a super-2 number, since 2×812721531² = 1321032573901967922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (812721131) 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, 10186 + ... + 41583.

It is an arithmetic number, because the mean of its divisors is an integer number (135482090).

Almost surely, 2^812721531 is an apocalyptic number.

812721531 is a deficient number, since it is larger than the sum of its proper divisors (271135189).

812721531 is a wasteful number, since it uses less digits than its factorization.

812721531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57005.

The product of its digits is 3360, while the sum is 30.

The square root of 812721531 is about 28508.2712734392. The cubic root of 812721531 is about 933.2125883624.

Adding to 812721531 its reverse (135127218), we get a palindrome (947848749).

The spelling of 812721531 in words is "eight hundred twelve million, seven hundred twenty-one thousand, five hundred thirty-one".