2891631 has 4 divisors (see below), whose sum is σ = 3855512. Its totient is φ = 1927752.

The previous prime is 2891599. The next prime is 2891639. The reversal of 2891631 is 1361982.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 2891631 - 2⁵ = 2891599 is a prime.

It is a super-2 number, since 2×2891631² = 16723059680322, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2891639) 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, 481936 + ... + 481941.

It is an arithmetic number, because the mean of its divisors is an integer number (963878).

2^2891631 is an apocalyptic number.

2891631 is a deficient number, since it is larger than the sum of its proper divisors (963881).

2891631 is an equidigital number, since it uses as much as digits as its factorization.

2891631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 963880.

The product of its digits is 2592, while the sum is 30.

The square root of 2891631 is about 1700.4796382198. The cubic root of 2891631 is about 142.4670037483.

The spelling of 2891631 in words is "two million, eight hundred ninety-one thousand, six hundred thirty-one".