21053552 has 40 divisors (see below), whose sum is σ = 44330496. Its totient is φ = 9628416.

The previous prime is 21053537. The next prime is 21053563. The reversal of 21053552 is 25535012.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26018 + ... + 26814.

Almost surely, 2^21053552 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 21053552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22165248).

21053552 is an abundant number, since it is smaller than the sum of its proper divisors (23276944).

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

21053552 is a wasteful number, since it uses less digits than its factorization.

21053552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 945 (or 939 counting only the distinct ones).

The product of its (nonzero) digits is 1500, while the sum is 23.

The square root of 21053552 is about 4588.4149768738. The cubic root of 21053552 is about 276.1267358864.

Adding to 21053552 its reverse (25535012), we get a palindrome (46588564).

The spelling of 21053552 in words is "twenty-one million, fifty-three thousand, five hundred fifty-two".