21328140 has 48 divisors (see below), whose sum is σ = 59941728. Its totient is φ = 5666304.

The previous prime is 21328117. The next prime is 21328157. The reversal of 21328140 is 4182312.

It is a zygodrome in base 9.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21904 + ... + 22856.

It is an arithmetic number, because the mean of its divisors is an integer number (1248786).

Almost surely, 2^21328140 is an apocalyptic number.

21328140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21328140 is an abundant number, since it is smaller than the sum of its proper divisors (38613588).

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

21328140 is a wasteful number, since it uses less digits than its factorization.

21328140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1338 (or 1336 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21328140 is about 4618.2399244734. The cubic root of 21328140 is about 277.3220025624.

The spelling of 21328140 in words is "twenty-one million, three hundred twenty-eight thousand, one hundred forty".