21992923 has 2 divisors, whose sum is σ = 21992924. Its totient is φ = 21992922.

The previous prime is 21992897. The next prime is 21992941. The reversal of 21992923 is 32929912.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21992923 is a prime.

It is equal to p_1388854 and since 21992923 and 1388854 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21992723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10996461 + 10996462.

It is an arithmetic number, because the mean of its divisors is an integer number (10996462).

Almost surely, 2^21992923 is an apocalyptic number.

21992923 is a deficient number, since it is larger than the sum of its proper divisors (1).

21992923 is an equidigital number, since it uses as much as digits as its factorization.

21992923 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17496, while the sum is 37.

The square root of 21992923 is about 4689.6612884088. The cubic root of 21992923 is about 280.1738843397.

The spelling of 21992923 in words is "twenty-one million, nine hundred ninety-two thousand, nine hundred twenty-three".