31279531 has 2 divisors, whose sum is σ = 31279532. Its totient is φ = 31279530.

The previous prime is 31279513. The next prime is 31279559. The reversal of 31279531 is 13597213.

Together with previous prime (31279513) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31279531 - 2¹¹ = 31277483 is a prime.

It is a super-2 number, since 2×31279531² = 1956818119159922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31279493 and 31279502.

It is not a weakly prime, because it can be changed into another prime (31279571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15639765 + 15639766.

It is an arithmetic number, because the mean of its divisors is an integer number (15639766).

Almost surely, 2^31279531 is an apocalyptic number.

31279531 is a deficient number, since it is larger than the sum of its proper divisors (1).

31279531 is an equidigital number, since it uses as much as digits as its factorization.

31279531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5670, while the sum is 31.

The square root of 31279531 is about 5592.8106529723. The cubic root of 31279531 is about 315.0794491795.

The spelling of 31279531 in words is "thirty-one million, two hundred seventy-nine thousand, five hundred thirty-one".