21552013 has 12 divisors (see below), whose sum is σ = 25147260. Its totient is φ = 18416832.

The previous prime is 21552007. The next prime is 21552031. The reversal of 21552013 is 31025512.

It can be written as a sum of positive squares in 2 ways, for example, as 2350089 + 19201924 = 1533^2 + 4382^2 .

It is not a de Polignac number, because 21552013 - 2¹⁷ = 21420941 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21552043) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 27495 + ... + 28267.

It is an arithmetic number, because the mean of its divisors is an integer number (2095605).

Almost surely, 2^21552013 is an apocalyptic number.

It is an amenable number.

21552013 is a deficient number, since it is larger than the sum of its proper divisors (3595247).

21552013 is an equidigital number, since it uses as much as digits as its factorization.

21552013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1356 (or 1349 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 21552013 is about 4642.4145657190. The cubic root of 21552013 is about 278.2889401352.

Adding to 21552013 its reverse (31025512), we get a palindrome (52577525).

The spelling of 21552013 in words is "twenty-one million, five hundred fifty-two thousand, thirteen".