31439681 has 16 divisors (see below), whose sum is σ = 40973184. Its totient is φ = 23410944.

The previous prime is 31439659. The next prime is 31439687. The reversal of 31439681 is 18693413.

It is a cyclic number.

It is not a de Polignac number, because 31439681 - 2¹⁴ = 31423297 is a prime.

It is a super-2 number, since 2×31439681² = 1976907082763522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (31439687) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8615 + ... + 11708.

It is an arithmetic number, because the mean of its divisors is an integer number (2560824).

Almost surely, 2^31439681 is an apocalyptic number.

It is an amenable number.

31439681 is a deficient number, since it is larger than the sum of its proper divisors (9533503).

31439681 is a wasteful number, since it uses less digits than its factorization.

31439681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20360.

The product of its digits is 15552, while the sum is 35.

The square root of 31439681 is about 5607.1098615954. The cubic root of 31439681 is about 315.6162656277.

The spelling of 31439681 in words is "thirty-one million, four hundred thirty-nine thousand, six hundred eighty-one".