31146721 has 2 divisors, whose sum is σ = 31146722. Its totient is φ = 31146720.

The previous prime is 31146701. The next prime is 31146733. The reversal of 31146721 is 12764113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16516096 + 14630625 = 4064^2 + 3825^2 .

It is a cyclic number.

It is not a de Polignac number, because 31146721 - 2²¹ = 29049569 is a prime.

It is not a weakly prime, because it can be changed into another prime (31146701) 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, 15573360 + 15573361.

It is an arithmetic number, because the mean of its divisors is an integer number (15573361).

Almost surely, 2^31146721 is an apocalyptic number.

It is an amenable number.

31146721 is a deficient number, since it is larger than the sum of its proper divisors (1).

31146721 is an equidigital number, since it uses as much as digits as its factorization.

31146721 is an odious number, because the sum of its binary digits is odd.

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

The square root of 31146721 is about 5580.9247441620. The cubic root of 31146721 is about 314.6328838087.

The spelling of 31146721 in words is "thirty-one million, one hundred forty-six thousand, seven hundred twenty-one".