31380931 has 2 divisors, whose sum is σ = 31380932. Its totient is φ = 31380930.

The previous prime is 31380893. The next prime is 31380941. The reversal of 31380931 is 13908313.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31380931 - 2¹¹ = 31378883 is a prime.

It is a super-2 number, since 2×31380931² = 1969525660853522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31380931.

It is not a weakly prime, because it can be changed into another prime (31380941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15690465 + 15690466.

It is an arithmetic number, because the mean of its divisors is an integer number (15690466).

Almost surely, 2^31380931 is an apocalyptic number.

31380931 is a deficient number, since it is larger than the sum of its proper divisors (1).

31380931 is an equidigital number, since it uses as much as digits as its factorization.

31380931 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 31380931 is about 5601.8685275540. The cubic root of 31380931 is about 315.4195501304.

The spelling of 31380931 in words is "thirty-one million, three hundred eighty thousand, nine hundred thirty-one".