21375423 has 6 divisors (see below), whose sum is σ = 30875624. Its totient is φ = 14250276.

The previous prime is 21375413. The next prime is 21375439. The reversal of 21375423 is 32457312.

It is not a de Polignac number, because 21375423 - 2⁶ = 21375359 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 (21375413) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1187515 + ... + 1187532.

Almost surely, 2^21375423 is an apocalyptic number.

21375423 is a deficient number, since it is larger than the sum of its proper divisors (9500201).

21375423 is a wasteful number, since it uses less digits than its factorization.

21375423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2375053 (or 2375050 counting only the distinct ones).

The product of its digits is 5040, while the sum is 27.

The square root of 21375423 is about 4623.3562484412. The cubic root of 21375423 is about 277.5267858244.

The spelling of 21375423 in words is "twenty-one million, three hundred seventy-five thousand, four hundred twenty-three".