21644322 has 32 divisors (see below), whose sum is σ = 49766400. Its totient is φ = 6147408.

The previous prime is 21644321. The next prime is 21644339. The reversal of 21644322 is 22344612.

It is a junction number, because it is equal to n+sod(n) for n = 21644292 and 21644301.

It is not an unprimeable number, because it can be changed into a prime (21644321) 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, 6079 + ... + 8957.

It is an arithmetic number, because the mean of its divisors is an integer number (1555200).

Almost surely, 2^21644322 is an apocalyptic number.

21644322 is an abundant number, since it is smaller than the sum of its proper divisors (28122078).

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

21644322 is a wasteful number, since it uses less digits than its factorization.

21644322 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3070.

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

The square root of 21644322 is about 4652.3458598862. The cubic root of 21644322 is about 278.6856855248.

Adding to 21644322 its reverse (22344612), we get a palindrome (43988934).

The spelling of 21644322 in words is "twenty-one million, six hundred forty-four thousand, three hundred twenty-two".