31660621 has 2 divisors, whose sum is σ = 31660622. Its totient is φ = 31660620.

The previous prime is 31660619. The next prime is 31660633. The reversal of 31660621 is 12606613.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30680521 + 980100 = 5539^2 + 990^2 .

It is a cyclic number.

It is not a de Polignac number, because 31660621 - 2¹ = 31660619 is a prime.

It is a super-3 number, since 3×31660621³ (a number of 23 digits) contains 333 as substring.

Together with 31660619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31660691) 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, 15830310 + 15830311.

It is an arithmetic number, because the mean of its divisors is an integer number (15830311).

Almost surely, 2^31660621 is an apocalyptic number.

It is an amenable number.

31660621 is a deficient number, since it is larger than the sum of its proper divisors (1).

31660621 is an equidigital number, since it uses as much as digits as its factorization.

31660621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 31660621 is about 5626.7771414905. Note that the first 3 decimals coincide. The cubic root of 31660621 is about 316.3538637223.

The spelling of 31660621 in words is "thirty-one million, six hundred sixty thousand, six hundred twenty-one".