2157145 has 4 divisors (see below), whose sum is σ = 2588580. Its totient is φ = 1725712.

The previous prime is 2157131. The next prime is 2157149. The reversal of 2157145 is 5417512.

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 1098304 + 1058841 = 1048^2 + 1029^2 .

It is a cyclic number.

It is not a de Polignac number, because 2157145 - 2⁷ = 2157017 is a prime.

2157145 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2157149) 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, 215710 + ... + 215719.

It is an arithmetic number, because the mean of its divisors is an integer number (647145).

2^2157145 is an apocalyptic number.

It is an amenable number.

2157145 is a deficient number, since it is larger than the sum of its proper divisors (431435).

2157145 is an equidigital number, since it uses as much as digits as its factorization.

2157145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431434.

The product of its digits is 1400, while the sum is 25.

The square root of 2157145 is about 1468.7222337801. The cubic root of 2157145 is about 129.2091034108.

The spelling of 2157145 in words is "two million, one hundred fifty-seven thousand, one hundred forty-five".