7891591 has 2 divisors, whose sum is σ = 7891592. Its totient is φ = 7891590.

The previous prime is 7891589. The next prime is 7891603. The reversal of 7891591 is 1951987.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 7891591 - 2¹ = 7891589 is a prime.

It is a super-2 number, since 2×7891591² = 124554417022562, which contains 22 as substring.

Together with 7891589, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7891991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3945795 + 3945796.

It is an arithmetic number, because the mean of its divisors is an integer number (3945796).

Almost surely, 2^7891591 is an apocalyptic number.

7891591 is a deficient number, since it is larger than the sum of its proper divisors (1).

7891591 is an equidigital number, since it uses as much as digits as its factorization.

7891591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22680, while the sum is 40.

The square root of 7891591 is about 2809.1975722615. The cubic root of 7891591 is about 199.0924799319.

The spelling of 7891591 in words is "seven million, eight hundred ninety-one thousand, five hundred ninety-one".