2881661 has 4 divisors (see below), whose sum is σ = 2898492. Its totient is φ = 2864832.

The previous prime is 2881657. The next prime is 2881699. The reversal of 2881661 is 1661882.

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 2785561 + 96100 = 1669^2 + 310^2 .

It is a cyclic number.

It is not a de Polignac number, because 2881661 - 2² = 2881657 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2881621) 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, 8156 + ... + 8501.

It is an arithmetic number, because the mean of its divisors is an integer number (724623).

2^2881661 is an apocalyptic number.

It is an amenable number.

2881661 is a deficient number, since it is larger than the sum of its proper divisors (16831).

2881661 is a wasteful number, since it uses less digits than its factorization.

2881661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16830.

The product of its digits is 4608, while the sum is 32.

The square root of 2881661 is about 1697.5455811259. The cubic root of 2881661 is about 142.3030787738.

The spelling of 2881661 in words is "two million, eight hundred eighty-one thousand, six hundred sixty-one".