21913884 has 72 divisors (see below), whose sum is σ = 59714928. Its totient is φ = 6750720.

The previous prime is 21913861. The next prime is 21913933. The reversal of 21913884 is 48831912.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

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 23 ways as a sum of consecutive naturals, for example, 37039 + ... + 37625.

It is an arithmetic number, because the mean of its divisors is an integer number (829374).

Almost surely, 2^21913884 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21913884, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29857464).

21913884 is an abundant number, since it is smaller than the sum of its proper divisors (37801044).

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

21913884 is a wasteful number, since it uses less digits than its factorization.

21913884 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 675 (or 670 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 21913884 is about 4681.2267622921. The cubic root of 21913884 is about 279.8378482908.

The spelling of 21913884 in words is "twenty-one million, nine hundred thirteen thousand, eight hundred eighty-four".