31087213 has 2 divisors, whose sum is σ = 31087214. Its totient is φ = 31087212.

The previous prime is 31087207. The next prime is 31087219. The reversal of 31087213 is 31278013.

It is a balanced prime because it is at equal distance from previous prime (31087207) and next prime (31087219).

It can be written as a sum of positive squares in only one way, i.e., 22867524 + 8219689 = 4782^2 + 2867^2 .

It is a cyclic number.

It is not a de Polignac number, because 31087213 - 2⁵ = 31087181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31087219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15543606 + 15543607.

It is an arithmetic number, because the mean of its divisors is an integer number (15543607).

Almost surely, 2^31087213 is an apocalyptic number.

It is an amenable number.

31087213 is a deficient number, since it is larger than the sum of its proper divisors (1).

31087213 is an equidigital number, since it uses as much as digits as its factorization.

31087213 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 31087213 is about 5575.5908207113. The cubic root of 31087213 is about 314.4323799815.

The spelling of 31087213 in words is "thirty-one million, eighty-seven thousand, two hundred thirteen".