31339681 has 2 divisors, whose sum is σ = 31339682. Its totient is φ = 31339680.

The previous prime is 31339673. The next prime is 31339697. The reversal of 31339681 is 18693313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31192225 + 147456 = 5585^2 + 384^2 .

It is a cyclic number.

It is not a de Polignac number, because 31339681 - 2³ = 31339673 is a prime.

It is a super-2 number, since 2×31339681² = 1964351210363522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31339601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15669840 + 15669841.

It is an arithmetic number, because the mean of its divisors is an integer number (15669841).

Almost surely, 2^31339681 is an apocalyptic number.

It is an amenable number.

31339681 is a deficient number, since it is larger than the sum of its proper divisors (1).

31339681 is an equidigital number, since it uses as much as digits as its factorization.

31339681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11664, while the sum is 34.

The square root of 31339681 is about 5598.1855096093. The cubic root of 31339681 is about 315.2812839799.

The spelling of 31339681 in words is "thirty-one million, three hundred thirty-nine thousand, six hundred eighty-one".