21307392 has 126 divisors (see below), whose sum is σ = 65384553. Its totient is φ = 6684672.

The previous prime is 21307381. The next prime is 21307397. The reversal of 21307392 is 29370312.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 19501056 + 1806336 = 4416^2 + 1344^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=3264.

It is not an unprimeable number, because it can be changed into a prime (21307397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1253368 + ... + 1253384.

Almost surely, 2^21307392 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21307392

21307392 is an abundant number, since it is smaller than the sum of its proper divisors (44077161).

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

21307392 is an equidigital number, since it uses as much as digits as its factorization.

21307392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66 (or 22 counting only the distinct ones).

The product of its (nonzero) digits is 2268, while the sum is 27.

The square root of 21307392 is about 4615.9930675858. The cubic root of 21307392 is about 277.2320471685.

The spelling of 21307392 in words is "twenty-one million, three hundred seven thousand, three hundred ninety-two".