21246245 has 4 divisors (see below), whose sum is σ = 25495500. Its totient is φ = 16996992.

The previous prime is 21246229. The next prime is 21246263. The reversal of 21246245 is 54264212.

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 7392961 + 13853284 = 2719^2 + 3722^2 .

It is a cyclic number.

It is not a de Polignac number, because 21246245 - 2⁴ = 21246229 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2124620 + ... + 2124629.

It is an arithmetic number, because the mean of its divisors is an integer number (6373875).

Almost surely, 2^21246245 is an apocalyptic number.

It is an amenable number.

21246245 is a deficient number, since it is larger than the sum of its proper divisors (4249255).

21246245 is an equidigital number, since it uses as much as digits as its factorization.

21246245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4249254.

The product of its digits is 3840, while the sum is 26.

The square root of 21246245 is about 4609.3649237178. The cubic root of 21246245 is about 276.9665970400.

The spelling of 21246245 in words is "twenty-one million, two hundred forty-six thousand, two hundred forty-five".