21326580 has 72 divisors (see below), whose sum is σ = 70578144. Its totient is φ = 5169600.

The previous prime is 21326573. The next prime is 21326587. The reversal of 21326580 is 8562312.

21326580 is a `hidden beast` number, since 2 + 1 + 3 + 2 + 658 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21326573) and next prime (21326587).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21326587) 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 23 ways as a sum of consecutive naturals, for example, 3406 + ... + 7365.

It is an arithmetic number, because the mean of its divisors is an integer number (980252).

Almost surely, 2^21326580 is an apocalyptic number.

21326580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21326580 is an abundant number, since it is smaller than the sum of its proper divisors (49251564).

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

21326580 is a wasteful number, since it uses less digits than its factorization.

21326580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10797 (or 10792 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 21326580 is about 4618.0710258722. The cubic root of 21326580 is about 277.3152410278.

Adding to 21326580 its reverse (8562312), we get a palindrome (29888892).

The spelling of 21326580 in words is "twenty-one million, three hundred twenty-six thousand, five hundred eighty".