21361923 has 24 divisors (see below), whose sum is σ = 34384896. Its totient is φ = 12668400.

The previous prime is 21361919. The next prime is 21361931. The reversal of 21361923 is 32916312.

21361923 is a `hidden beast` number, since 21 + 3 + 619 + 23 = 666.

It is not a de Polignac number, because 21361923 - 2² = 21361919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21361933) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2358 + ... + 6948.

It is an arithmetic number, because the mean of its divisors is an integer number (1432704).

Almost surely, 2^21361923 is an apocalyptic number.

21361923 is a deficient number, since it is larger than the sum of its proper divisors (13022973).

21361923 is a wasteful number, since it uses less digits than its factorization.

21361923 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4655 (or 4652 counting only the distinct ones).

The product of its digits is 1944, while the sum is 27.

The square root of 21361923 is about 4621.8960395059. The cubic root of 21361923 is about 277.4683479847.

The spelling of 21361923 in words is "twenty-one million, three hundred sixty-one thousand, nine hundred twenty-three".