31166021 has 2 divisors, whose sum is σ = 31166022. Its totient is φ = 31166020.

The previous prime is 31166011. The next prime is 31166111. The reversal of 31166021 is 12066113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18105025 + 13060996 = 4255^2 + 3614^2 .

It is a cyclic number.

It is not a de Polignac number, because 31166021 - 2¹⁸ = 30903877 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31165984 and 31166002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31166011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15583010 + 15583011.

It is an arithmetic number, because the mean of its divisors is an integer number (15583011).

Almost surely, 2^31166021 is an apocalyptic number.

It is an amenable number.

31166021 is a deficient number, since it is larger than the sum of its proper divisors (1).

31166021 is an equidigital number, since it uses as much as digits as its factorization.

31166021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 31166021 is about 5582.6535805117. The cubic root of 31166021 is about 314.6978575913.

The spelling of 31166021 in words is "thirty-one million, one hundred sixty-six thousand, twenty-one".