21649268 has 12 divisors (see below), whose sum is σ = 37920960. Its totient is φ = 10814712.

The previous prime is 21649247. The next prime is 21649273. The reversal of 21649268 is 86294612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4805 + ... + 8147.

It is an arithmetic number, because the mean of its divisors is an integer number (3160080).

Almost surely, 2^21649268 is an apocalyptic number.

It is an amenable number.

21649268 is a deficient number, since it is larger than the sum of its proper divisors (16271692).

21649268 is a wasteful number, since it uses less digits than its factorization.

21649268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4966 (or 4964 counting only the distinct ones).

The product of its digits is 41472, while the sum is 38.

The square root of 21649268 is about 4652.8773893151. The cubic root of 21649268 is about 278.7069116370.

The spelling of 21649268 in words is "twenty-one million, six hundred forty-nine thousand, two hundred sixty-eight".