216785431731 has 32 divisors (see below), whose sum is σ = 319402828800. Its totient is φ = 129686618880.

The previous prime is 216785431727. The next prime is 216785431741. The reversal of 216785431731 is 137134587612.

It is not a de Polignac number, because 216785431731 - 2² = 216785431727 is a prime.

It is a super-2 number, since 2×216785431731² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (216785431711) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11975335 + ... + 11993423.

It is an arithmetic number, because the mean of its divisors is an integer number (9981338400).

Almost surely, 2^216785431731 is an apocalyptic number.

216785431731 is a deficient number, since it is larger than the sum of its proper divisors (102617397069).

216785431731 is a wasteful number, since it uses less digits than its factorization.

216785431731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22779.

The product of its digits is 846720, while the sum is 48.

The spelling of 216785431731 in words is "two hundred sixteen billion, seven hundred eighty-five million, four hundred thirty-one thousand, seven hundred thirty-one".