31609031 has 2 divisors, whose sum is σ = 31609032. Its totient is φ = 31609030.

The previous prime is 31608971. The next prime is 31609033. The reversal of 31609031 is 13090613.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31609031 is a prime.

It is a super-2 number, since 2×31609031² = 1998261681517922, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 31609033, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_1951142 and since 31609031 and 1951142 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 31608988 and 31609006.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31609033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15804515 + 15804516.

It is an arithmetic number, because the mean of its divisors is an integer number (15804516).

Almost surely, 2^31609031 is an apocalyptic number.

31609031 is a deficient number, since it is larger than the sum of its proper divisors (1).

31609031 is an equidigital number, since it uses as much as digits as its factorization.

31609031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 486, while the sum is 23.

The square root of 31609031 is about 5622.1909430399. The cubic root of 31609031 is about 316.1819407042.

Adding to 31609031 its reverse (13090613), we get a palindrome (44699644).

The spelling of 31609031 in words is "thirty-one million, six hundred nine thousand, thirty-one".