7991891422 has 4 divisors (see below), whose sum is σ = 11987837136. Its totient is φ = 3995945710.

The previous prime is 7991891363. The next prime is 7991891423. The reversal of 7991891422 is 2241981997.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 2241981997 = 13877 ⋅161561.

It is a self number, because there is not a number n which added to its sum of digits gives 7991891422.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7991891423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1997972854 + ... + 1997972857.

It is an arithmetic number, because the mean of its divisors is an integer number (2996959284).

Almost surely, 2^7991891422 is an apocalyptic number.

7991891422 is a deficient number, since it is larger than the sum of its proper divisors (3995945714).

7991891422 is a wasteful number, since it uses less digits than its factorization.

7991891422 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3995945713.

The product of its digits is 653184, while the sum is 52.

The square root of 7991891422 is about 89397.3792792608. The cubic root of 7991891422 is about 1999.3240567428.

The spelling of 7991891422 in words is "seven billion, nine hundred ninety-one million, eight hundred ninety-one thousand, four hundred twenty-two".