20316921 has 16 divisors (see below), whose sum is σ = 28911168. Its totient is φ = 12646400.

The previous prime is 20316911. The next prime is 20316929. The reversal of 20316921 is 12961302.

It is a cyclic number.

It is not a de Polignac number, because 20316921 - 2⁹ = 20316409 is a prime.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 20316891 and 20316900.

It is not an unprimeable number, because it can be changed into a prime (20316929) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5161 + ... + 8201.

It is an arithmetic number, because the mean of its divisors is an integer number (1806948).

Almost surely, 2^20316921 is an apocalyptic number.

It is an amenable number.

20316921 is a deficient number, since it is larger than the sum of its proper divisors (8594247).

20316921 is a wasteful number, since it uses less digits than its factorization.

20316921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3192.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 20316921 is about 4507.4295335590. The cubic root of 20316921 is about 272.8680143978.

The spelling of 20316921 in words is "twenty million, three hundred sixteen thousand, nine hundred twenty-one".