21868584 has 64 divisors (see below), whose sum is σ = 57628800. Its totient is φ = 6902016.

The previous prime is 21868573. The next prime is 21868589. The reversal of 21868584 is 48586812.

It is not an unprimeable number, because it can be changed into a prime (21868589) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 95382 + ... + 95610.

It is an arithmetic number, because the mean of its divisors is an integer number (900450).

Almost surely, 2^21868584 is an apocalyptic number.

21868584 is a gapful number since it is divisible by the number (24) 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 21868584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28814400).

21868584 is an abundant number, since it is smaller than the sum of its proper divisors (35760216).

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

21868584 is a wasteful number, since it uses less digits than its factorization.

21868584 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 434 (or 430 counting only the distinct ones).

The product of its digits is 122880, while the sum is 42.

The square root of 21868584 is about 4676.3857839148. The cubic root of 21868584 is about 279.6448899581.

The spelling of 21868584 in words is "twenty-one million, eight hundred sixty-eight thousand, five hundred eighty-four".