856665537956 has 24 divisors (see below), whose sum is σ = 1642087089720. Its totient is φ = 389235456512.

The previous prime is 856665537907. The next prime is 856665537961. The reversal of 856665537956 is 659735566658.

It can be written as a sum of positive squares in 4 ways, for example, as 508782624100 + 347882913856 = 713290^2 + 589816^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 856665537956.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 217205315 + ... + 217209258.

It is an arithmetic number, because the mean of its divisors is an integer number (68420295405).

Almost surely, 2^856665537956 is an apocalyptic number.

It is an amenable number.

856665537956 is a deficient number, since it is larger than the sum of its proper divisors (785421551764).

856665537956 is a wasteful number, since it uses less digits than its factorization.

856665537956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 434414623 (or 434414621 counting only the distinct ones).

The product of its digits is 1224720000, while the sum is 71.

The spelling of 856665537956 in words is "eight hundred fifty-six billion, six hundred sixty-five million, five hundred thirty-seven thousand, nine hundred fifty-six".