2145509 has 4 divisors (see below), whose sum is σ = 2238816. Its totient is φ = 2052204.

The previous prime is 2145497. The next prime is 2145529. The reversal of 2145509 is 9055412.

2145509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2145509 - 2¹² = 2141413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2145529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46619 + ... + 46664.

It is an arithmetic number, because the mean of its divisors is an integer number (559704).

2^2145509 is an apocalyptic number.

It is an amenable number.

2145509 is a deficient number, since it is larger than the sum of its proper divisors (93307).

2145509 is an equidigital number, since it uses as much as digits as its factorization.

2145509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93306.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 2145509 is about 1464.7556110150. The cubic root of 2145509 is about 128.9763592678.

Subtracting 2145509 from its reverse (9055412), we obtain a triangular number (6909903 = T₃₇₁₇).

The spelling of 2145509 in words is "two million, one hundred forty-five thousand, five hundred nine".