7891891 has 6 divisors (see below), whose sum is σ = 9180420. Its totient is φ = 6764436.

The previous prime is 7891867. The next prime is 7891901. The reversal of 7891891 is 1981987.

It is not a de Polignac number, because 7891891 - 2⁹ = 7891379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7891801) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 80481 + ... + 80578.

It is an arithmetic number, because the mean of its divisors is an integer number (1530070).

Almost surely, 2^7891891 is an apocalyptic number.

7891891 is a deficient number, since it is larger than the sum of its proper divisors (1288529).

7891891 is a wasteful number, since it uses less digits than its factorization.

7891891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161073 (or 161066 counting only the distinct ones).

The product of its digits is 36288, while the sum is 43.

The square root of 7891891 is about 2809.2509677848. The cubic root of 7891891 is about 199.0950027433.

The spelling of 7891891 in words is "seven million, eight hundred ninety-one thousand, eight hundred ninety-one".