21873923 has 2 divisors, whose sum is σ = 21873924. Its totient is φ = 21873922.

The previous prime is 21873911. The next prime is 21873931. The reversal of 21873923 is 32937812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21873923 - 2²⁰ = 20825347 is a prime.

It is not a weakly prime, because it can be changed into another prime (21873953) 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 as a sum of consecutive naturals, namely, 10936961 + 10936962.

It is an arithmetic number, because the mean of its divisors is an integer number (10936962).

Almost surely, 2^21873923 is an apocalyptic number.

21873923 is a deficient number, since it is larger than the sum of its proper divisors (1).

21873923 is an equidigital number, since it uses as much as digits as its factorization.

21873923 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 35.

The square root of 21873923 is about 4676.9565959072. The cubic root of 21873923 is about 279.6676456241.

The spelling of 21873923 in words is "twenty-one million, eight hundred seventy-three thousand, nine hundred twenty-three".