31721461 has 2 divisors, whose sum is σ = 31721462. Its totient is φ = 31721460.

The previous prime is 31721441. The next prime is 31721467. The reversal of 31721461 is 16412713.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25816561 + 5904900 = 5081^2 + 2430^2 .

It is a cyclic number.

It is not a de Polignac number, because 31721461 - 2⁵ = 31721429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31721467) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15860730 + 15860731.

It is an arithmetic number, because the mean of its divisors is an integer number (15860731).

Almost surely, 2^31721461 is an apocalyptic number.

It is an amenable number.

31721461 is a deficient number, since it is larger than the sum of its proper divisors (1).

31721461 is an equidigital number, since it uses as much as digits as its factorization.

31721461 is an evil number, because the sum of its binary digits is even.

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

The square root of 31721461 is about 5632.1808387160. The cubic root of 31721461 is about 316.5563724233.

The spelling of 31721461 in words is "thirty-one million, seven hundred twenty-one thousand, four hundred sixty-one".