31870213 has 2 divisors, whose sum is σ = 31870214. Its totient is φ = 31870212.

The previous prime is 31870199. The next prime is 31870219. The reversal of 31870213 is 31207813.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27384289 + 4485924 = 5233^2 + 2118^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31870213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31870219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15935106 + 15935107.

It is an arithmetic number, because the mean of its divisors is an integer number (15935107).

Almost surely, 2^31870213 is an apocalyptic number.

It is an amenable number.

31870213 is a deficient number, since it is larger than the sum of its proper divisors (1).

31870213 is an equidigital number, since it uses as much as digits as its factorization.

31870213 is an evil number, because the sum of its binary digits is even.

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

The square root of 31870213 is about 5645.3709355542. The cubic root of 31870213 is about 317.0504120949.

The spelling of 31870213 in words is "thirty-one million, eight hundred seventy thousand, two hundred thirteen".