31528213 has 2 divisors, whose sum is σ = 31528214. Its totient is φ = 31528212.

The previous prime is 31528207. The next prime is 31528229. The reversal of 31528213 is 31282513.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 29517489 + 2010724 = 5433^2 + 1418^2 .

It is a cyclic number.

It is not a de Polignac number, because 31528213 - 2⁹ = 31527701 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31528283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15764106 + 15764107.

It is an arithmetic number, because the mean of its divisors is an integer number (15764107).

Almost surely, 2^31528213 is an apocalyptic number.

It is an amenable number.

31528213 is a deficient number, since it is larger than the sum of its proper divisors (1).

31528213 is an equidigital number, since it uses as much as digits as its factorization.

31528213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 25.

The square root of 31528213 is about 5614.9989314336. The cubic root of 31528213 is about 315.9122392887.

The spelling of 31528213 in words is "thirty-one million, five hundred twenty-eight thousand, two hundred thirteen".