21102245 has 4 divisors (see below), whose sum is σ = 25322700. Its totient is φ = 16881792.

The previous prime is 21102239. The next prime is 21102251. The reversal of 21102245 is 54220112.

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

It is an interprime number because it is at equal distance from previous prime (21102239) and next prime (21102251).

It can be written as a sum of positive squares in 2 ways, for example, as 8300161 + 12802084 = 2881^2 + 3578^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102245 - 2⁶ = 21102181 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, 2110220 + ... + 2110229.

It is an arithmetic number, because the mean of its divisors is an integer number (6330675).

Almost surely, 2^21102245 is an apocalyptic number.

It is an amenable number.

21102245 is a deficient number, since it is larger than the sum of its proper divisors (4220455).

21102245 is an equidigital number, since it uses as much as digits as its factorization.

21102245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4220454.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 21102245 is about 4593.7179930858. The cubic root of 21102245 is about 276.3394487948.

Adding to 21102245 its reverse (54220112), we get a palindrome (75322357).

The spelling of 21102245 in words is "twenty-one million, one hundred two thousand, two hundred forty-five".