2661509 has 4 divisors (see below), whose sum is σ = 2665740. Its totient is φ = 2657280.

The previous prime is 2661497. The next prime is 2661517. The reversal of 2661509 is 9051662.

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 770884 + 1890625 = 878^2 + 1375^2 .

It is a cyclic number.

It is not a de Polignac number, because 2661509 - 2⁴ = 2661493 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2661569) 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, 962 + ... + 2499.

It is an arithmetic number, because the mean of its divisors is an integer number (666435).

2^2661509 is an apocalyptic number.

It is an amenable number.

2661509 is a deficient number, since it is larger than the sum of its proper divisors (4231).

2661509 is an equidigital number, since it uses as much as digits as its factorization.

2661509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4230.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 2661509 is about 1631.4131910709. The cubic root of 2661509 is about 138.5827940108.

The spelling of 2661509 in words is "two million, six hundred sixty-one thousand, five hundred nine".