21614640 has 80 divisors (see below), whose sum is σ = 67683168. Its totient is φ = 5705728.

The previous prime is 21614597. The next prime is 21614651. The reversal of 21614640 is 4641612.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21614640.

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, 26722 + ... + 27518.

Almost surely, 2^21614640 is an apocalyptic number.

21614640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21614640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33841584).

21614640 is an abundant number, since it is smaller than the sum of its proper divisors (46068528).

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

21614640 is a wasteful number, since it uses less digits than its factorization.

21614640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 926 (or 920 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 21614640 is about 4649.1547618895. The cubic root of 21614640 is about 278.5582351223.

The spelling of 21614640 in words is "twenty-one million, six hundred fourteen thousand, six hundred forty".