2991881 has 4 divisors (see below), whose sum is σ = 3167892. Its totient is φ = 2815872.

The previous prime is 2991871. The next prime is 2991883. The reversal of 2991881 is 1881992.

2991881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 1690000 + 1301881 = 1300^2 + 1141^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2991881 is a prime.

It is a super-2 number, since 2×2991881² = 17902703836322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2991883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87980 + ... + 88013.

It is an arithmetic number, because the mean of its divisors is an integer number (791973).

2^2991881 is an apocalyptic number.

It is an amenable number.

2991881 is a deficient number, since it is larger than the sum of its proper divisors (176011).

2991881 is a wasteful number, since it uses less digits than its factorization.

2991881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176010.

The product of its digits is 10368, while the sum is 38.

The square root of 2991881 is about 1729.7054662572. The cubic root of 2991881 is about 144.0947325468.

The spelling of 2991881 in words is "two million, nine hundred ninety-one thousand, eight hundred eighty-one".