21633138 has 12 divisors (see below), whose sum is σ = 46871838. Its totient is φ = 7211040.

The previous prime is 21633127. The next prime is 21633149. The reversal of 21633138 is 83133612.

It is a happy number.

21633138 is a `hidden beast` number, since 21 + 633 + 1 + 3 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (21633127) and next prime (21633149).

It can be written as a sum of positive squares in only one way, i.e., 11309769 + 10323369 = 3363^2 + 3213^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 600903 + ... + 600938.

Almost surely, 2^21633138 is an apocalyptic number.

21633138 is an abundant number, since it is smaller than the sum of its proper divisors (25238700).

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

21633138 is a wasteful number, since it uses less digits than its factorization.

21633138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1201849 (or 1201846 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 21633138 is about 4651.1437303098. The cubic root of 21633138 is about 278.6376766644.

The spelling of 21633138 in words is "twenty-one million, six hundred thirty-three thousand, one hundred thirty-eight".