31093921 has 2 divisors, whose sum is σ = 31093922. Its totient is φ = 31093920.

The previous prime is 31093913. The next prime is 31093943. The reversal of 31093921 is 12939013.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27248400 + 3845521 = 5220^2 + 1961^2 .

It is an emirp because it is prime and its reverse (12939013) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31093921 - 2³ = 31093913 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31093921.

It is not a weakly prime, because it can be changed into another prime (31093991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15546960 + 15546961.

It is an arithmetic number, because the mean of its divisors is an integer number (15546961).

Almost surely, 2^31093921 is an apocalyptic number.

It is an amenable number.

31093921 is a deficient number, since it is larger than the sum of its proper divisors (1).

31093921 is an equidigital number, since it uses as much as digits as its factorization.

31093921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1458, while the sum is 28.

The square root of 31093921 is about 5576.1923388635. The cubic root of 31093921 is about 314.4549944319.

The spelling of 31093921 in words is "thirty-one million, ninety-three thousand, nine hundred twenty-one".