21552356 has 18 divisors (see below), whose sum is σ = 43874838. Its totient is φ = 9236640.

The previous prime is 21552353. The next prime is 21552371. The reversal of 21552356 is 65325512.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 21473956 + 78400 = 4634^2 + 280^2 .

It is not an unprimeable number, because it can be changed into a prime (21552353) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 54785 + ... + 55176.

It is an arithmetic number, because the mean of its divisors is an integer number (2437491).

Almost surely, 2^21552356 is an apocalyptic number.

It is an amenable number.

21552356 is an abundant number, since it is smaller than the sum of its proper divisors (22322482).

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

21552356 is a wasteful number, since it uses less digits than its factorization.

21552356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109979 (or 109970 counting only the distinct ones).

The product of its digits is 9000, while the sum is 29.

The square root of 21552356 is about 4642.4515075550. The cubic root of 21552356 is about 278.2904164489.

Adding to 21552356 its reverse (65325512), we get a palindrome (86877868).

The spelling of 21552356 in words is "twenty-one million, five hundred fifty-two thousand, three hundred fifty-six".