21226580 has 24 divisors (see below), whose sum is σ = 44665992. Its totient is φ = 8473472.

The previous prime is 21226571. The next prime is 21226603. The reversal of 21226580 is 8562212.

It can be written as a sum of positive squares in 4 ways, for example, as 3147076 + 18079504 = 1774^2 + 4252^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14774 + ... + 16146.

It is an arithmetic number, because the mean of its divisors is an integer number (1861083).

Almost surely, 2^21226580 is an apocalyptic number.

21226580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21226580 is an abundant number, since it is smaller than the sum of its proper divisors (23439412).

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

21226580 is a wasteful number, since it uses less digits than its factorization.

21226580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2155 (or 2153 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 21226580 is about 4607.2312726843. The cubic root of 21226580 is about 276.8811195138.

Adding to 21226580 its reverse (8562212), we get a palindrome (29788792).

The spelling of 21226580 in words is "twenty-one million, two hundred twenty-six thousand, five hundred eighty".