2157245 has 4 divisors (see below), whose sum is σ = 2588700. Its totient is φ = 1725792.

The previous prime is 2157229. The next prime is 2157247. The reversal of 2157245 is 5427512.

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 1214404 + 942841 = 1102^2 + 971^2 .

It is a cyclic number.

It is not a de Polignac number, because 2157245 - 2⁴ = 2157229 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2157247) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 215720 + ... + 215729.

It is an arithmetic number, because the mean of its divisors is an integer number (647175).

2^2157245 is an apocalyptic number.

It is an amenable number.

2157245 is a deficient number, since it is larger than the sum of its proper divisors (431455).

2157245 is an equidigital number, since it uses as much as digits as its factorization.

2157245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431454.

The product of its digits is 2800, while the sum is 26.

The square root of 2157245 is about 1468.7562765823. The cubic root of 2157245 is about 129.2110999866.

The spelling of 2157245 in words is "two million, one hundred fifty-seven thousand, two hundred forty-five".