2158009 has 6 divisors (see below), whose sum is σ = 2510394. Its totient is φ = 1849680.

The previous prime is 2157989. The next prime is 2158019. The reversal of 2158009 is 9008512.

It can be written as a sum of positive squares in only one way, i.e., 1882384 + 275625 = 1372^2 + 525^2 .

It is not a de Polignac number, because 2158009 - 2¹¹ = 2155961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2158019) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 21972 + ... + 22069.

It is an arithmetic number, because the mean of its divisors is an integer number (418399).

2^2158009 is an apocalyptic number.

It is an amenable number.

2158009 is a deficient number, since it is larger than the sum of its proper divisors (352385).

2158009 is an equidigital number, since it uses as much as digits as its factorization.

2158009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44055 (or 44048 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 2158009 is about 1469.0163375538. The cubic root of 2158009 is about 129.2263517899.

The spelling of 2158009 in words is "two million, one hundred fifty-eight thousand, nine".