2551809 has 16 divisors (see below), whose sum is σ = 3729600. Its totient is φ = 1542336.

The previous prime is 2551793. The next prime is 2551817. The reversal of 2551809 is 9081552.

It is not a de Polignac number, because 2551809 - 2⁴ = 2551793 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2551859) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1747 + ... + 2855.

It is an arithmetic number, because the mean of its divisors is an integer number (233100).

It is a Proth number, since it is equal to 623 ⋅ 2¹² + 1 and 623 < 2¹².

2^2551809 is an apocalyptic number.

It is an amenable number.

2551809 is a deficient number, since it is larger than the sum of its proper divisors (1177791).

2551809 is a wasteful number, since it uses less digits than its factorization.

2551809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1184.

The product of its (nonzero) digits is 3600, while the sum is 30.

The square root of 2551809 is about 1597.4382617178. The cubic root of 2551809 is about 136.6520197139.

The spelling of 2551809 in words is "two million, five hundred fifty-one thousand, eight hundred nine".