2609861 has 4 divisors (see below), whose sum is σ = 2618412. Its totient is φ = 2601312.

The previous prime is 2609813. The next prime is 2609899. The reversal of 2609861 is 1689062.

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 302500 + 2307361 = 550^2 + 1519^2 .

It is a cyclic number.

It is not a de Polignac number, because 2609861 - 2¹⁴ = 2593477 is a prime.

It is a super-3 number, since 3×2609861³ = 53330221516742233143, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2609261) 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, 3800 + ... + 4433.

It is an arithmetic number, because the mean of its divisors is an integer number (654603).

2^2609861 is an apocalyptic number.

It is an amenable number.

2609861 is a deficient number, since it is larger than the sum of its proper divisors (8551).

2609861 is an equidigital number, since it uses as much as digits as its factorization.

2609861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8550.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 2609861 is about 1615.5064221476. The cubic root of 2609861 is about 137.6805078320.

The spelling of 2609861 in words is "two million, six hundred nine thousand, eight hundred sixty-one".