856777938129 has 45 divisors (see below), whose sum is σ = 1351035122283. Its totient is φ = 541022941008.

The previous prime is 856777938119. The next prime is 856777938161. The reversal of 856777938129 is 921839777658.

The square root of 856777938129 is 925623.

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

856777938129 is a `hidden beast` number, since 8 + 567 + 7 + 7 + 9 + 38 + 1 + 29 = 666.

It can be written as a sum of positive squares in only one way, i.e., 186429650625 + 670348287504 = 431775^2 + 818748^2 .

It is not a de Polignac number, because 856777938129 - 2²⁵ = 856744383697 is a prime.

It is not an unprimeable number, because it can be changed into a prime (856777938119) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 158278827 + ... + 158284239.

Almost surely, 2^856777938129 is an apocalyptic number.

856777938129 is the 925623-rd square number.

856777938129 is the 462812-nd centered octagonal number.

It is an amenable number.

856777938129 is a deficient number, since it is larger than the sum of its proper divisors (494257184154).

856777938129 is an frugal number, since it uses more digits than its factorization.

856777938129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10876 (or 5435 counting only the distinct ones).

The product of its digits is 320060160, while the sum is 72.

The spelling of 856777938129 in words is "eight hundred fifty-six billion, seven hundred seventy-seven million, nine hundred thirty-eight thousand, one hundred twenty-nine".