21328307 has 36 divisors (see below), whose sum is σ = 29206800. Its totient is φ = 15238080.

The previous prime is 21328303. The next prime is 21328309. The reversal of 21328307 is 70382312.

It is not a de Polignac number, because 21328307 - 2² = 21328303 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21328303) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 143069 + ... + 143217.

It is an arithmetic number, because the mean of its divisors is an integer number (811300).

Almost surely, 2^21328307 is an apocalyptic number.

21328307 is a deficient number, since it is larger than the sum of its proper divisors (7878493).

21328307 is a wasteful number, since it uses less digits than its factorization.

21328307 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204 (or 180 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 21328307 is about 4618.2580049192. The cubic root of 21328307 is about 277.3227263738.

The spelling of 21328307 in words is "twenty-one million, three hundred twenty-eight thousand, three hundred seven".