21230256 has 40 divisors (see below), whose sum is σ = 55090224. Its totient is φ = 7045120.

The previous prime is 21230249. The next prime is 21230273. The reversal of 21230256 is 65203212.

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, 11476 + ... + 13196.

Almost surely, 2^21230256 is an apocalyptic number.

It is an amenable number.

21230256 is an abundant number, since it is smaller than the sum of its proper divisors (33859968).

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

21230256 is a wasteful number, since it uses less digits than its factorization.

21230256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1989 (or 1983 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 21230256 is about 4607.6301934943. The cubic root of 21230256 is about 276.8971019321.

Adding to 21230256 its reverse (65203212), we get a palindrome (86433468).

The spelling of 21230256 in words is "twenty-one million, two hundred thirty thousand, two hundred fifty-six".