31646561 has 2 divisors, whose sum is σ = 31646562. Its totient is φ = 31646560.

The previous prime is 31646539. The next prime is 31646603. The reversal of 31646561 is 16564613.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31528225 + 118336 = 5615^2 + 344^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31646561 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31646521) 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, 15823280 + 15823281.

It is an arithmetic number, because the mean of its divisors is an integer number (15823281).

Almost surely, 2^31646561 is an apocalyptic number.

It is an amenable number.

31646561 is a deficient number, since it is larger than the sum of its proper divisors (1).

31646561 is an equidigital number, since it uses as much as digits as its factorization.

31646561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 32.

The square root of 31646561 is about 5625.5276196993. The cubic root of 31646561 is about 316.3070274763.

The spelling of 31646561 in words is "thirty-one million, six hundred forty-six thousand, five hundred sixty-one".