21328580 has 48 divisors (see below), whose sum is σ = 55130880. Its totient is φ = 6749568.

The previous prime is 21328561. The next prime is 21328597. The reversal of 21328580 is 8582312.

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 15 ways as a sum of consecutive naturals, for example, 4040 + ... + 7679.

It is an arithmetic number, because the mean of its divisors is an integer number (1148560).

Almost surely, 2^21328580 is an apocalyptic number.

21328580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21328580 is an abundant number, since it is smaller than the sum of its proper divisors (33802300).

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

21328580 is a wasteful number, since it uses less digits than its factorization.

21328580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11748 (or 11746 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 29.

The square root of 21328580 is about 4618.2875614236. The cubic root of 21328580 is about 277.3239096023.

The spelling of 21328580 in words is "twenty-one million, three hundred twenty-eight thousand, five hundred eighty".