31687013 has 2 divisors, whose sum is σ = 31687014. Its totient is φ = 31687012.

The previous prime is 31686989. The next prime is 31687021. The reversal of 31687013 is 31078613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17833729 + 13853284 = 4223^2 + 3722^2 .

It is an emirp because it is prime and its reverse (31078613) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31687013 - 2¹⁴ = 31670629 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31687043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15843506 + 15843507.

It is an arithmetic number, because the mean of its divisors is an integer number (15843507).

Almost surely, 2^31687013 is an apocalyptic number.

It is an amenable number.

31687013 is a deficient number, since it is larger than the sum of its proper divisors (1).

31687013 is an equidigital number, since it uses as much as digits as its factorization.

31687013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 31687013 is about 5629.1218675740. The cubic root of 31687013 is about 316.4417425240.

Subtracting from 31687013 its reverse (31078613), we obtain a square (608400 = 780²).

The spelling of 31687013 in words is "thirty-one million, six hundred eighty-seven thousand, thirteen".