21551338 has 4 divisors (see below), whose sum is σ = 32327010. Its totient is φ = 10775668.

The previous prime is 21551323. The next prime is 21551351. The reversal of 21551338 is 83315512.

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

It can be written as a sum of positive squares in only one way, i.e., 19158129 + 2393209 = 4377^2 + 1547^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5387833 + ... + 5387836.

Almost surely, 2^21551338 is an apocalyptic number.

21551338 is a deficient number, since it is larger than the sum of its proper divisors (10775672).

21551338 is a wasteful number, since it uses less digits than its factorization.

21551338 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10775671.

The product of its digits is 3600, while the sum is 28.

The square root of 21551338 is about 4642.3418659121. The cubic root of 21551338 is about 278.2860348072.

The spelling of 21551338 in words is "twenty-one million, five hundred fifty-one thousand, three hundred thirty-eight".