21649256 has 16 divisors (see below), whose sum is σ = 42357600. Its totient is φ = 10353904.

The previous prime is 21649247. The next prime is 21649273. The reversal of 21649256 is 65294612.

It is a happy number.

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, 58646 + ... + 59013.

It is an arithmetic number, because the mean of its divisors is an integer number (2647350).

Almost surely, 2^21649256 is an apocalyptic number.

It is an amenable number.

21649256 is a deficient number, since it is larger than the sum of its proper divisors (20708344).

21649256 is a wasteful number, since it uses less digits than its factorization.

21649256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117688 (or 117684 counting only the distinct ones).

The product of its digits is 25920, while the sum is 35.

The square root of 21649256 is about 4652.8760997903. The cubic root of 21649256 is about 278.7068601421.

The spelling of 21649256 in words is "twenty-one million, six hundred forty-nine thousand, two hundred fifty-six".