21868258 has 8 divisors (see below), whose sum is σ = 33689052. Its totient is φ = 10638576.

The previous prime is 21868247. The next prime is 21868289. The reversal of 21868258 is 85286812.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 21836929 + 31329 = 4673^2 + 177^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21868258.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 147685 + ... + 147832.

Almost surely, 2^21868258 is an apocalyptic number.

21868258 is a deficient number, since it is larger than the sum of its proper divisors (11820794).

21868258 is a wasteful number, since it uses less digits than its factorization.

21868258 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295556.

The product of its digits is 61440, while the sum is 40.

The square root of 21868258 is about 4676.3509278069. The cubic root of 21868258 is about 279.6435003743.

The spelling of 21868258 in words is "twenty-one million, eight hundred sixty-eight thousand, two hundred fifty-eight".