821512015129 has 27 divisors (see below), whose sum is σ = 898965188823. Its totient is φ = 750389832192.

The previous prime is 821512015039. The next prime is 821512015133. The reversal of 821512015129 is 921510215128.

The square root of 821512015129 is 906373.

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

It can be written as a sum of positive squares in 13 ways, for example, as 340081417225 + 481430597904 = 583165^2 + 693852^2 .

It is not a de Polignac number, because 821512015129 - 2⁷ = 821512015001 is a prime.

It is not an unprimeable number, because it can be changed into a prime (821512015529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1331461629 + ... + 1331462245.

Almost surely, 2^821512015129 is an apocalyptic number.

821512015129 is the 906373-rd square number.

821512015129 is the 453187-th centered octagonal number.

It is an amenable number.

821512015129 is a deficient number, since it is larger than the sum of its proper divisors (77453173694).

821512015129 is an frugal number, since it uses more digits than its factorization.

821512015129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1486 (or 743 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 37.

The spelling of 821512015129 in words is "eight hundred twenty-one billion, five hundred twelve million, fifteen thousand, one hundred twenty-nine".