21322644 has 36 divisors (see below), whose sum is σ = 57877344. Its totient is φ = 6092016.

The previous prime is 21322621. The next prime is 21322661. The reversal of 21322644 is 44622312.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17544 + ... + 18719.

It is an arithmetic number, because the mean of its divisors is an integer number (1607704).

Almost surely, 2^21322644 is an apocalyptic number.

It is an amenable number.

21322644 is an abundant number, since it is smaller than the sum of its proper divisors (36554700).

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

21322644 is a wasteful number, since it uses less digits than its factorization.

21322644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36284 (or 36275 counting only the distinct ones).

The product of its digits is 2304, while the sum is 24.

The square root of 21322644 is about 4617.6448542520. The cubic root of 21322644 is about 277.2981796902.

Adding to 21322644 its reverse (44622312), we get a palindrome (65944956).

The spelling of 21322644 in words is "twenty-one million, three hundred twenty-two thousand, six hundred forty-four".