31609691 has 2 divisors, whose sum is σ = 31609692. Its totient is φ = 31609690.

The previous prime is 31609679. The next prime is 31609693. The reversal of 31609691 is 19690613.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31609691 - 2¹⁰ = 31608667 is a prime.

It is a Sophie Germain prime.

Together with 31609693, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31609693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15804845 + 15804846.

It is an arithmetic number, because the mean of its divisors is an integer number (15804846).

Almost surely, 2^31609691 is an apocalyptic number.

31609691 is a deficient number, since it is larger than the sum of its proper divisors (1).

31609691 is an equidigital number, since it uses as much as digits as its factorization.

31609691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8748, while the sum is 35.

The square root of 31609691 is about 5622.2496387122. The cubic root of 31609691 is about 316.1841413267.

The spelling of 31609691 in words is "thirty-one million, six hundred nine thousand, six hundred ninety-one".