21149556 has 24 divisors (see below), whose sum is σ = 49443744. Its totient is φ = 7036320.

The previous prime is 21149549. The next prime is 21149561. The reversal of 21149556 is 65594112.

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 7 ways as a sum of consecutive naturals, for example, 6346 + ... + 9086.

It is an arithmetic number, because the mean of its divisors is an integer number (2060156).

Almost surely, 2^21149556 is an apocalyptic number.

It is an amenable number.

21149556 is an abundant number, since it is smaller than the sum of its proper divisors (28294188).

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

21149556 is a wasteful number, since it uses less digits than its factorization.

21149556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3391 (or 3389 counting only the distinct ones).

The product of its digits is 10800, while the sum is 33.

The square root of 21149556 is about 4598.8646424960. The cubic root of 21149556 is about 276.5458113138.

The spelling of 21149556 in words is "twenty-one million, one hundred forty-nine thousand, five hundred fifty-six".