21792245 has 4 divisors (see below), whose sum is σ = 26150700. Its totient is φ = 17433792.

The previous prime is 21792241. The next prime is 21792263. The reversal of 21792245 is 54229712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14002564 + 7789681 = 3742^2 + 2791^2 .

It is a cyclic number.

It is not a de Polignac number, because 21792245 - 2² = 21792241 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21792241) 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 3 ways as a sum of consecutive naturals, for example, 2179220 + ... + 2179229.

It is an arithmetic number, because the mean of its divisors is an integer number (6537675).

Almost surely, 2^21792245 is an apocalyptic number.

It is an amenable number.

21792245 is a deficient number, since it is larger than the sum of its proper divisors (4358455).

21792245 is an equidigital number, since it uses as much as digits as its factorization.

21792245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4358454.

The product of its digits is 10080, while the sum is 32.

The square root of 21792245 is about 4668.2164688455. The cubic root of 21792245 is about 279.3191151708.

The spelling of 21792245 in words is "twenty-one million, seven hundred ninety-two thousand, two hundred forty-five".