2991531 has 16 divisors (see below), whose sum is σ = 4336640. Its totient is φ = 1827360.

The previous prime is 2991523. The next prime is 2991551. The reversal of 2991531 is 1351992.

It is not a de Polignac number, because 2991531 - 2³ = 2991523 is a prime.

It is a super-2 number, since 2×2991531² = 17898515447922, which contains 22 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 (2991511) 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 15 ways as a sum of consecutive naturals, for example, 921 + ... + 2613.

It is an arithmetic number, because the mean of its divisors is an integer number (271040).

2^2991531 is an apocalyptic number.

2991531 is a deficient number, since it is larger than the sum of its proper divisors (1345109).

2991531 is a wasteful number, since it uses less digits than its factorization.

2991531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1746.

The product of its digits is 2430, while the sum is 30.

The square root of 2991531 is about 1729.6042900039. The cubic root of 2991531 is about 144.0891134370.

It can be divided in two parts, 299 and 1531, that added together give a triangular number (1830 = T₆₀).

The spelling of 2991531 in words is "two million, nine hundred ninety-one thousand, five hundred thirty-one".