2871661 has 4 divisors (see below), whose sum is σ = 3092572. Its totient is φ = 2650752.

The previous prime is 2871643. The next prime is 2871689. The reversal of 2871661 is 1661782.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1661782 = 2 ⋅830891.

It can be written as a sum of positive squares in 2 ways, for example, as 372100 + 2499561 = 610^2 + 1581^2 .

It is not a de Polignac number, because 2871661 - 2⁵ = 2871629 is a prime.

It is a super-3 number, since 3×2871661³ = 71042913694777133343, which contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2871611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110436 + ... + 110461.

It is an arithmetic number, because the mean of its divisors is an integer number (773143).

2^2871661 is an apocalyptic number.

It is an amenable number.

2871661 is a deficient number, since it is larger than the sum of its proper divisors (220911).

2871661 is a wasteful number, since it uses less digits than its factorization.

2871661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220910.

The product of its digits is 4032, while the sum is 31.

The square root of 2871661 is about 1694.5975923505. The cubic root of 2871661 is about 142.1382802953.

The spelling of 2871661 in words is "two million, eight hundred seventy-one thousand, six hundred sixty-one".