856217131 has 24 divisors (see below), whose sum is σ = 1088996400. Its totient is φ = 665683200.

The previous prime is 856217129. The next prime is 856217137. The reversal of 856217131 is 131712658.

It is a happy number.

It is not a de Polignac number, because 856217131 - 2¹ = 856217129 is a prime.

It is a super-2 number, since 2×856217131² = 1466215550835742322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (856217137) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 279295 + ... + 282343.

It is an arithmetic number, because the mean of its divisors is an integer number (45374850).

Almost surely, 2^856217131 is an apocalyptic number.

856217131 is a deficient number, since it is larger than the sum of its proper divisors (232779269).

856217131 is a wasteful number, since it uses less digits than its factorization.

856217131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3595 (or 3588 counting only the distinct ones).

The product of its digits is 10080, while the sum is 34.

The square root of 856217131 is about 29261.1881337720. The cubic root of 856217131 is about 949.5721548963.

Adding to 856217131 its reverse (131712658), we get a palindrome (987929789).

The spelling of 856217131 in words is "eight hundred fifty-six million, two hundred seventeen thousand, one hundred thirty-one".