31338221 has 2 divisors, whose sum is σ = 31338222. Its totient is φ = 31338220.

The previous prime is 31338173. The next prime is 31338247. The reversal of 31338221 is 12283313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30360100 + 978121 = 5510^2 + 989^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31338221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31338721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15669110 + 15669111.

It is an arithmetic number, because the mean of its divisors is an integer number (15669111).

Almost surely, 2^31338221 is an apocalyptic number.

It is an amenable number.

31338221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31338221 is an equidigital number, since it uses as much as digits as its factorization.

31338221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864, while the sum is 23.

The square root of 31338221 is about 5598.0551086962. The cubic root of 31338221 is about 315.2763879736.

The spelling of 31338221 in words is "thirty-one million, three hundred thirty-eight thousand, two hundred twenty-one".