4891591 has 2 divisors, whose sum is σ = 4891592. Its totient is φ = 4891590.

The previous prime is 4891567. The next prime is 4891639. The reversal of 4891591 is 1951984.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 4891591 - 2⁵ = 4891559 is a prime.

It is a super-2 number, since 2×4891591² = 47855325022562, which contains 22 as substring.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 4891591.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4891501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2445795 + 2445796.

It is an arithmetic number, because the mean of its divisors is an integer number (2445796).

Almost surely, 2^4891591 is an apocalyptic number.

4891591 is a deficient number, since it is larger than the sum of its proper divisors (1).

4891591 is an equidigital number, since it uses as much as digits as its factorization.

4891591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 37.

The square root of 4891591 is about 2211.6941470285. The cubic root of 4891591 is about 169.7527085011.

It can be divided in two parts, 489 and 1591, that added together give a triangular number (2080 = T₆₄).

The spelling of 4891591 in words is "four million, eight hundred ninety-one thousand, five hundred ninety-one".