2891661 has 16 divisors (see below), whose sum is σ = 4012800. Its totient is φ = 1850688.

The previous prime is 2891657. The next prime is 2891671. The reversal of 2891661 is 1661982.

It is not a de Polignac number, because 2891661 - 2² = 2891657 is a prime.

2891661 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2891671) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11980 + ... + 12218.

It is an arithmetic number, because the mean of its divisors is an integer number (250800).

2^2891661 is an apocalyptic number.

It is an amenable number.

2891661 is a deficient number, since it is larger than the sum of its proper divisors (1121139).

2891661 is a wasteful number, since it uses less digits than its factorization.

2891661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388.

The product of its digits is 5184, while the sum is 33.

The square root of 2891661 is about 1700.4884592375. The cubic root of 2891661 is about 142.4674964340.

The spelling of 2891661 in words is "two million, eight hundred ninety-one thousand, six hundred sixty-one".