21224588 has 48 divisors (see below), whose sum is σ = 46738944. Its totient is φ = 8192640.

The previous prime is 21224579. The next prime is 21224591. The reversal of 21224588 is 88542212.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a congruent number.

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, 41945 + ... + 42447.

It is an arithmetic number, because the mean of its divisors is an integer number (973728).

Almost surely, 2^21224588 is an apocalyptic number.

21224588 is a gapful number since it is divisible by the number (28) 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 21224588, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23369472).

21224588 is an abundant number, since it is smaller than the sum of its proper divisors (25514356).

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

21224588 is a wasteful number, since it uses less digits than its factorization.

21224588 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662 (or 660 counting only the distinct ones).

The product of its digits is 10240, while the sum is 32.

The square root of 21224588 is about 4607.0150857144. The cubic root of 21224588 is about 276.8724579764.

It can be divided in two parts, 21224 and 588, that added together give a palindrome (21812).

The spelling of 21224588 in words is "twenty-one million, two hundred twenty-four thousand, five hundred eighty-eight".