21560020 has 12 divisors (see below), whose sum is σ = 45276084. Its totient is φ = 8624000.

The previous prime is 21560017. The next prime is 21560027. The reversal of 21560020 is 2006512.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 5846724 + 15713296 = 2418^2 + 3964^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21559976 and 21560003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21560027) 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 3 ways as a sum of consecutive naturals, for example, 538981 + ... + 539020.

It is an arithmetic number, because the mean of its divisors is an integer number (3773007).

Almost surely, 2^21560020 is an apocalyptic number.

21560020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21560020 is an abundant number, since it is smaller than the sum of its proper divisors (23716064).

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

21560020 is a wasteful number, since it uses less digits than its factorization.

21560020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1078010 (or 1078008 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21560020 is about 4643.2768601495. The cubic root of 21560020 is about 278.3233991538.

Adding to 21560020 its reverse (2006512), we get a palindrome (23566532).

The spelling of 21560020 in words is "twenty-one million, five hundred sixty thousand, twenty".