21923873 has 4 divisors (see below), whose sum is σ = 21978948. Its totient is φ = 21868800.

The previous prime is 21923833. The next prime is 21923903. The reversal of 21923873 is 37832912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13897984 + 8025889 = 3728^2 + 2833^2 .

It is a cyclic number.

It is not a de Polignac number, because 21923873 - 2⁶ = 21923809 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21923813) 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, 26936 + ... + 27737.

It is an arithmetic number, because the mean of its divisors is an integer number (5494737).

Almost surely, 2^21923873 is an apocalyptic number.

It is an amenable number.

21923873 is a deficient number, since it is larger than the sum of its proper divisors (55075).

21923873 is an equidigital number, since it uses as much as digits as its factorization.

21923873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55074.

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

The square root of 21923873 is about 4682.2935619203. The cubic root of 21923873 is about 279.8803613029.

The spelling of 21923873 in words is "twenty-one million, nine hundred twenty-three thousand, eight hundred seventy-three".