21322320 has 40 divisors (see below), whose sum is σ = 66099936. Its totient is φ = 5685888.

The previous prime is 21322319. The next prime is 21322331. The reversal of 21322320 is 2322312.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21322320.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44182 + ... + 44661.

Almost surely, 2^21322320 is an apocalyptic number.

21322320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21322320 is an abundant number, since it is smaller than the sum of its proper divisors (44777616).

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

21322320 is a wasteful number, since it uses less digits than its factorization.

21322320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88859 (or 88853 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 21322320 is about 4617.6097712994. The cubic root of 21322320 is about 277.2967751573.

Adding to 21322320 its reverse (2322312), we get a palindrome (23644632).

The spelling of 21322320 in words is "twenty-one million, three hundred twenty-two thousand, three hundred twenty".