21279423 has 36 divisors (see below), whose sum is σ = 32753112. Its totient is φ = 12276000.

The previous prime is 21279421. The next prime is 21279431. The reversal of 21279423 is 32497212.

It is not a de Polignac number, because 21279423 - 2¹ = 21279421 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21279421) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 348813 + ... + 348873.

Almost surely, 2^21279423 is an apocalyptic number.

21279423 is a deficient number, since it is larger than the sum of its proper divisors (11473689).

21279423 is a wasteful number, since it uses less digits than its factorization.

21279423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148 (or 106 counting only the distinct ones).

The product of its digits is 6048, while the sum is 30.

The square root of 21279423 is about 4612.9624971378. The cubic root of 21279423 is about 277.1106918143.

The spelling of 21279423 in words is "twenty-one million, two hundred seventy-nine thousand, four hundred twenty-three".