21814640 has 20 divisors (see below), whose sum is σ = 50719224. Its totient is φ = 8725824.

The previous prime is 21814633. The next prime is 21814703. The reversal of 21814640 is 4641812.

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 136262 + ... + 136421.

Almost surely, 2^21814640 is an apocalyptic number.

21814640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21814640 is an abundant number, since it is smaller than the sum of its proper divisors (28904584).

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

21814640 is a wasteful number, since it uses less digits than its factorization.

21814640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272696 (or 272690 counting only the distinct ones).

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

The square root of 21814640 is about 4670.6145205958. The cubic root of 21814640 is about 279.4147640284.

The spelling of 21814640 in words is "twenty-one million, eight hundred fourteen thousand, six hundred forty".