21043460 has 24 divisors (see below), whose sum is σ = 44294040. Its totient is φ = 8397824.

The previous prime is 21043457. The next prime is 21043481. The reversal of 21043460 is 6434012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 103684 + 20939776 = 322^2 + 4576^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

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, 10196 + ... + 12084.

It is an arithmetic number, because the mean of its divisors is an integer number (1845585).

Almost surely, 2^21043460 is an apocalyptic number.

21043460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21043460 is an abundant number, since it is smaller than the sum of its proper divisors (23250580).

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

21043460 is a wasteful number, since it uses less digits than its factorization.

21043460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2455 (or 2453 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 21043460 is about 4587.3151188904. The cubic root of 21043460 is about 276.0826084726.

Adding to 21043460 its reverse (6434012), we get a palindrome (27477472).

The spelling of 21043460 in words is "twenty-one million, forty-three thousand, four hundred sixty".