2509661 has 12 divisors (see below), whose sum is σ = 3153696. Its totient is φ = 1954920.

The previous prime is 2509649. The next prime is 2509679. The reversal of 2509661 is 1669052.

It is not a de Polignac number, because 2509661 - 2⁶ = 2509597 is a prime.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2509621) 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, 635 + ... + 2328.

It is an arithmetic number, because the mean of its divisors is an integer number (262808).

2^2509661 is an apocalyptic number.

It is an amenable number.

2509661 is a deficient number, since it is larger than the sum of its proper divisors (644035).

2509661 is a wasteful number, since it uses less digits than its factorization.

2509661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2992 (or 2981 counting only the distinct ones).

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

The square root of 2509661 is about 1584.1909607115. The cubic root of 2509661 is about 135.8954827026.

The spelling of 2509661 in words is "two million, five hundred nine thousand, six hundred sixty-one".