21423138 has 16 divisors (see below), whose sum is σ = 46741536. Its totient is φ = 6491840.

The previous prime is 21423119. The next prime is 21423161. The reversal of 21423138 is 83132412.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 162231 + ... + 162362.

It is an arithmetic number, because the mean of its divisors is an integer number (2921346).

Almost surely, 2^21423138 is an apocalyptic number.

21423138 is an abundant number, since it is smaller than the sum of its proper divisors (25318398).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21423138 is a wasteful number, since it uses less digits than its factorization.

21423138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324609.

The product of its digits is 1152, while the sum is 24.

The square root of 21423138 is about 4628.5135842946. The cubic root of 21423138 is about 277.7331341706.

The spelling of 21423138 in words is "twenty-one million, four hundred twenty-three thousand, one hundred thirty-eight".