2991931 has 4 divisors (see below), whose sum is σ = 3072832. Its totient is φ = 2911032.

The previous prime is 2991929. The next prime is 2991971. The reversal of 2991931 is 1391992.

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

It is a cyclic number.

It is not a de Polignac number, because 2991931 - 2¹ = 2991929 is a prime.

It is a super-2 number, since 2×2991931² = 17903302217522, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2991971) 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, 40395 + ... + 40468.

It is an arithmetic number, because the mean of its divisors is an integer number (768208).

2^2991931 is an apocalyptic number.

2991931 is a deficient number, since it is larger than the sum of its proper divisors (80901).

2991931 is an equidigital number, since it uses as much as digits as its factorization.

2991931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80900.

The product of its digits is 4374, while the sum is 34.

The square root of 2991931 is about 1729.7199195245. The cubic root of 2991931 is about 144.0955352410.

The spelling of 2991931 in words is "two million, nine hundred ninety-one thousand, nine hundred thirty-one".