7091991 has 6 divisors (see below), whose sum is σ = 10244000. Its totient is φ = 4727988.

The previous prime is 7091957. The next prime is 7091999. The reversal of 7091991 is 1991907.

It is not a de Polignac number, because 7091991 - 2⁶ = 7091927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7091999) 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 5 ways as a sum of consecutive naturals, for example, 393991 + ... + 394008.

Almost surely, 2^7091991 is an apocalyptic number.

7091991 is a deficient number, since it is larger than the sum of its proper divisors (3152009).

7091991 is a wasteful number, since it uses less digits than its factorization.

7091991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 788005 (or 788002 counting only the distinct ones).

The product of its (nonzero) digits is 5103, while the sum is 36.

The square root of 7091991 is about 2663.0792327680. The cubic root of 7091991 is about 192.1274381819.

The spelling of 7091991 in words is "seven million, ninety-one thousand, nine hundred ninety-one".