21086258 has 8 divisors (see below), whose sum is σ = 31710252. Its totient is φ = 10516176.

The previous prime is 21086251. The next prime is 21086279. The reversal of 21086258 is 85268012.

It can be written as a sum of positive squares in 2 ways, for example, as 21003889 + 82369 = 4583^2 + 287^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21086251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12485 + ... + 14072.

Almost surely, 2^21086258 is an apocalyptic number.

21086258 is a deficient number, since it is larger than the sum of its proper divisors (10623994).

21086258 is a wasteful number, since it uses less digits than its factorization.

21086258 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26956.

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 21086258 is about 4591.9775696316. The cubic root of 21086258 is about 276.2696465078.

It can be divided in two parts, 210 and 86258, that added together give a palindrome (86468).

The spelling of 21086258 in words is "twenty-one million, eighty-six thousand, two hundred fifty-eight".