31642561 has 2 divisors, whose sum is σ = 31642562. Its totient is φ = 31642560.

The previous prime is 31642553. The next prime is 31642603. The reversal of 31642561 is 16524613.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31640625 + 1936 = 5625^2 + 44^2 .

It is a cyclic number.

It is not a de Polignac number, because 31642561 - 2³ = 31642553 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31642531) 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, 15821280 + 15821281.

It is an arithmetic number, because the mean of its divisors is an integer number (15821281).

Almost surely, 2^31642561 is an apocalyptic number.

It is an amenable number.

31642561 is a deficient number, since it is larger than the sum of its proper divisors (1).

31642561 is an equidigital number, since it uses as much as digits as its factorization.

31642561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 28.

The square root of 31642561 is about 5625.1720862566. The cubic root of 31642561 is about 316.2937002628.

The spelling of 31642561 in words is "thirty-one million, six hundred forty-two thousand, five hundred sixty-one".