2857991 has 4 divisors (see below), whose sum is σ = 2935272. Its totient is φ = 2780712.

The previous prime is 2857973. The next prime is 2857993. The reversal of 2857991 is 1997582.

2857991 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 is a cyclic number.

It is not a de Polignac number, because 2857991 - 2¹⁰ = 2856967 is a prime.

It is a super-2 number, since 2×2857991² = 16336225112162, which contains 22 as substring.

It is an Ulam 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 (2857993) 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, 38585 + ... + 38658.

It is an arithmetic number, because the mean of its divisors is an integer number (733818).

2^2857991 is an apocalyptic number.

2857991 is a deficient number, since it is larger than the sum of its proper divisors (77281).

2857991 is an equidigital number, since it uses as much as digits as its factorization.

2857991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77280.

The product of its digits is 45360, while the sum is 41.

The square root of 2857991 is about 1690.5593748816. The cubic root of 2857991 is about 141.9123806488.

The spelling of 2857991 in words is "two million, eight hundred fifty-seven thousand, nine hundred ninety-one".