2551609 has 4 divisors (see below), whose sum is σ = 2554960. Its totient is φ = 2548260.

The previous prime is 2551607. The next prime is 2551639. The reversal of 2551609 is 9061552.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2551609 - 2¹ = 2551607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2551603) 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, 82 + ... + 2260.

It is an arithmetic number, because the mean of its divisors is an integer number (638740).

2^2551609 is an apocalyptic number.

It is an amenable number.

2551609 is a deficient number, since it is larger than the sum of its proper divisors (3351).

2551609 is a wasteful number, since it uses less digits than its factorization.

2551609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3350.

The product of its (nonzero) digits is 2700, while the sum is 28.

The square root of 2551609 is about 1597.3756602628. The cubic root of 2551609 is about 136.6484495515.

It can be divided in two parts, 2551 and 609, that added together give a triangular number (3160 = T₇₉).

The spelling of 2551609 in words is "two million, five hundred fifty-one thousand, six hundred nine".