21549056 has 26 divisors (see below), whose sum is σ = 43101042. Its totient is φ = 10772480.

The previous prime is 21549049. The next prime is 21549071. The reversal of 21549056 is 65094512.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20070400 + 1478656 = 4480^2 + 1216^2 .

It is a super-2 number, since 2×21549056² = 928723628982272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1466 + ... + 6726.

Almost surely, 2^21549056 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21549056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21550521).

21549056 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21549056 is an frugal number, since it uses more digits than its factorization.

21549056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5285 (or 5263 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 21549056 is about 4642.0960782819. The cubic root of 21549056 is about 278.2762121975.

The spelling of 21549056 in words is "twenty-one million, five hundred forty-nine thousand, fifty-six".