31668621 has 4 divisors (see below), whose sum is σ = 42224832. Its totient is φ = 21112412.

The previous prime is 31668607. The next prime is 31668653. The reversal of 31668621 is 12686613.

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 31668621 - 2⁶ = 31668557 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31668691) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5278101 + ... + 5278106.

It is an arithmetic number, because the mean of its divisors is an integer number (10556208).

Almost surely, 2^31668621 is an apocalyptic number.

It is an amenable number.

31668621 is a deficient number, since it is larger than the sum of its proper divisors (10556211).

31668621 is a wasteful number, since it uses less digits than its factorization.

31668621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10556210.

The product of its digits is 10368, while the sum is 33.

The square root of 31668621 is about 5627.4879831058. The cubic root of 31668621 is about 316.3805068908.

The spelling of 31668621 in words is "thirty-one million, six hundred sixty-eight thousand, six hundred twenty-one".