31636621 has 2 divisors, whose sum is σ = 31636622. Its totient is φ = 31636620.

The previous prime is 31636607. The next prime is 31636637. The reversal of 31636621 is 12663613.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 29268100 + 2368521 = 5410^2 + 1539^2 .

It is a cyclic number.

It is not a de Polignac number, because 31636621 - 2¹¹ = 31634573 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31636621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31636681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15818310 + 15818311.

It is an arithmetic number, because the mean of its divisors is an integer number (15818311).

Almost surely, 2^31636621 is an apocalyptic number.

It is an amenable number.

31636621 is a deficient number, since it is larger than the sum of its proper divisors (1).

31636621 is an equidigital number, since it uses as much as digits as its factorization.

31636621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 28.

The square root of 31636621 is about 5624.6440776284. The cubic root of 31636621 is about 316.2739072784.

The spelling of 31636621 in words is "thirty-one million, six hundred thirty-six thousand, six hundred twenty-one".