31363721 has 2 divisors, whose sum is σ = 31363722. Its totient is φ = 31363720.

The previous prime is 31363687. The next prime is 31363741. The reversal of 31363721 is 12736313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31360000 + 3721 = 5600^2 + 61^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31363721 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31363741) 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, 15681860 + 15681861.

It is an arithmetic number, because the mean of its divisors is an integer number (15681861).

Almost surely, 2^31363721 is an apocalyptic number.

It is an amenable number.

31363721 is a deficient number, since it is larger than the sum of its proper divisors (1).

31363721 is an equidigital number, since it uses as much as digits as its factorization.

31363721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2268, while the sum is 26.

The square root of 31363721 is about 5600.3322222882. The cubic root of 31363721 is about 315.3618785558.

It can be divided in two parts, 3136 and 3721, that multiplied together give a square (11669056 = 3416²).

The spelling of 31363721 in words is "thirty-one million, three hundred sixty-three thousand, seven hundred twenty-one".