31631621 has 4 divisors (see below), whose sum is σ = 36150432. Its totient is φ = 27112812.

The previous prime is 31631597. The next prime is 31631629. The reversal of 31631621 is 12613613.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 31631621 - 2¹⁴ = 31615237 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31631629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2259395 + ... + 2259408.

It is an arithmetic number, because the mean of its divisors is an integer number (9037608).

Almost surely, 2^31631621 is an apocalyptic number.

It is an amenable number.

31631621 is a deficient number, since it is larger than the sum of its proper divisors (4518811).

31631621 is an equidigital number, since it uses as much as digits as its factorization.

31631621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4518810.

The product of its digits is 648, while the sum is 23.

The square root of 31631621 is about 5624.1995874969. The cubic root of 31631621 is about 316.2572445965.

The spelling of 31631621 in words is "thirty-one million, six hundred thirty-one thousand, six hundred twenty-one".