2158645 has 4 divisors (see below), whose sum is σ = 2590380. Its totient is φ = 1726912.

The previous prime is 2158631. The next prime is 2158649. The reversal of 2158645 is 5468512.

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 1582564 + 576081 = 1258^2 + 759^2 .

It is a cyclic number.

It is not a de Polignac number, because 2158645 - 2¹¹ = 2156597 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

2158645 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2158649) 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, 215860 + ... + 215869.

It is an arithmetic number, because the mean of its divisors is an integer number (647595).

2^2158645 is an apocalyptic number.

It is an amenable number.

2158645 is a deficient number, since it is larger than the sum of its proper divisors (431735).

2158645 is an equidigital number, since it uses as much as digits as its factorization.

2158645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 431734.

The product of its digits is 9600, while the sum is 31.

The square root of 2158645 is about 1469.2327929910. The cubic root of 2158645 is about 129.2390455718.

The spelling of 2158645 in words is "two million, one hundred fifty-eight thousand, six hundred forty-five".