2155509 has 12 divisors (see below), whose sum is σ = 3198156. Its totient is φ = 1397952.

The previous prime is 2155499. The next prime is 2155511. The reversal of 2155509 is 9055512.

2155509 is a `hidden beast` number, since 2 + 155 + 509 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1199025 + 956484 = 1095^2 + 978^2 .

It is not a de Polignac number, because 2155509 - 2⁵ = 2155477 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2155519) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2904 + ... + 3569.

It is an arithmetic number, because the mean of its divisors is an integer number (266513).

2^2155509 is an apocalyptic number.

It is an amenable number.

2155509 is a deficient number, since it is larger than the sum of its proper divisors (1042647).

2155509 is a wasteful number, since it uses less digits than its factorization.

2155509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6516 (or 6513 counting only the distinct ones).

The product of its (nonzero) digits is 2250, while the sum is 27.

The square root of 2155509 is about 1468.1651814425. The cubic root of 2155509 is about 129.1764306644.

The spelling of 2155509 in words is "two million, one hundred fifty-five thousand, five hundred nine".