21230544 has 40 divisors (see below), whose sum is σ = 55032192. Its totient is φ = 7052800.

The previous prime is 21230537. The next prime is 21230549. The reversal of 21230544 is 44503212.

It is a Smith number, since the sum of its digits (21) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21230544.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21230549) 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 7 ways as a sum of consecutive naturals, for example, 18697 + ... + 19799.

Almost surely, 2^21230544 is an apocalyptic number.

21230544 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21230544 is an abundant number, since it is smaller than the sum of its proper divisors (33801648).

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

21230544 is a wasteful number, since it uses less digits than its factorization.

21230544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1515 (or 1509 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 21230544 is about 4607.6614458964. The cubic root of 21230544 is about 276.8983540132.

Adding to 21230544 its reverse (44503212), we get a palindrome (65733756).

The spelling of 21230544 in words is "twenty-one million, two hundred thirty thousand, five hundred forty-four".