2661591 has 8 divisors (see below), whose sum is σ = 3671280. Its totient is φ = 1713152.

The previous prime is 2661569. The next prime is 2661611. The reversal of 2661591 is 1951662.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2661591 - 2⁹ = 2661079 is a prime.

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2661541) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15210 + ... + 15383.

It is an arithmetic number, because the mean of its divisors is an integer number (458910).

2^2661591 is an apocalyptic number.

2661591 is a deficient number, since it is larger than the sum of its proper divisors (1009689).

2661591 is a wasteful number, since it uses less digits than its factorization.

2661591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30625.

The product of its digits is 3240, while the sum is 30.

The square root of 2661591 is about 1631.4383224627. The cubic root of 2661591 is about 138.5842172226.

It can be divided in two parts, 2661 and 591, that multiplied together give a triangular number (1572651 = T₁₇₇₃).

The spelling of 2661591 in words is "two million, six hundred sixty-one thousand, five hundred ninety-one".