21937423 has 8 divisors (see below), whose sum is σ = 23129568. Its totient is φ = 20765184.

The previous prime is 21937417. The next prime is 21937441. The reversal of 21937423 is 32473912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21937423 - 2⁹ = 21936911 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21937493) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2686 + ... + 7147.

It is an arithmetic number, because the mean of its divisors is an integer number (2891196).

Almost surely, 2^21937423 is an apocalyptic number.

21937423 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21937423 is a deficient number, since it is larger than the sum of its proper divisors (1192145).

21937423 is an equidigital number, since it uses as much as digits as its factorization.

21937423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9953.

The product of its digits is 9072, while the sum is 31.

The square root of 21937423 is about 4683.7402788797. The cubic root of 21937423 is about 279.9380092357.

The spelling of 21937423 in words is "twenty-one million, nine hundred thirty-seven thousand, four hundred twenty-three".