21326320 has 40 divisors (see below), whose sum is σ = 49818240. Its totient is φ = 8490240.

The previous prime is 21326309. The next prime is 21326351. The reversal of 21326320 is 2362312.

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

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, 21025 + ... + 22015.

It is an arithmetic number, because the mean of its divisors is an integer number (1245456).

Almost surely, 2^21326320 is an apocalyptic number.

21326320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21326320 is an abundant number, since it is smaller than the sum of its proper divisors (28491920).

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

21326320 is a wasteful number, since it uses less digits than its factorization.

21326320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1273 (or 1267 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 19.

The square root of 21326320 is about 4618.0428755047. The cubic root of 21326320 is about 277.3141140733.

Adding to 21326320 its reverse (2362312), we get a palindrome (23688632).

The spelling of 21326320 in words is "twenty-one million, three hundred twenty-six thousand, three hundred twenty".