21648140 has 24 divisors (see below), whose sum is σ = 48136032. Its totient is φ = 8149760.

The previous prime is 21648139. The next prime is 21648149. The reversal of 21648140 is 4184612.

It is not an unprimeable number, because it can be changed into a prime (21648149) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31496 + ... + 32175.

It is an arithmetic number, because the mean of its divisors is an integer number (2005668).

Almost surely, 2^21648140 is an apocalyptic number.

21648140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21648140 is an abundant number, since it is smaller than the sum of its proper divisors (26487892).

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

21648140 is a wasteful number, since it uses less digits than its factorization.

21648140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63697 (or 63695 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 26.

The square root of 21648140 is about 4652.7561724208. The cubic root of 21648140 is about 278.7020710291.

The spelling of 21648140 in words is "twenty-one million, six hundred forty-eight thousand, one hundred forty".