21426923 has 4 divisors (see below), whose sum is σ = 24487920. Its totient is φ = 18365928.

The previous prime is 21426907. The next prime is 21426929. The reversal of 21426923 is 32962412.

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

It is not a de Polignac number, because 21426923 - 2⁴ = 21426907 is a prime.

It is a super-2 number, since 2×21426923² = 918226058495858, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21426929) 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, 1530488 + ... + 1530501.

It is an arithmetic number, because the mean of its divisors is an integer number (6121980).

Almost surely, 2^21426923 is an apocalyptic number.

21426923 is a deficient number, since it is larger than the sum of its proper divisors (3060997).

21426923 is an equidigital number, since it uses as much as digits as its factorization.

21426923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3060996.

The product of its digits is 5184, while the sum is 29.

The square root of 21426923 is about 4628.9224448029. The cubic root of 21426923 is about 277.7494896645.

The spelling of 21426923 in words is "twenty-one million, four hundred twenty-six thousand, nine hundred twenty-three".