7991691819 has 4 divisors (see below), whose sum is σ = 10655589096. Its totient is φ = 5327794544.

The previous prime is 7991691797. The next prime is 7991691839. The reversal of 7991691819 is 9181961997.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 7991691819 - 2⁵ = 7991691787 is a prime.

It is a super-2 number, since 2×7991691819² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (7991691839) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1331948634 + ... + 1331948639.

It is an arithmetic number, because the mean of its divisors is an integer number (2663897274).

Almost surely, 2^7991691819 is an apocalyptic number.

7991691819 is a deficient number, since it is larger than the sum of its proper divisors (2663897277).

7991691819 is a wasteful number, since it uses less digits than its factorization.

7991691819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2663897276.

The product of its digits is 2204496, while the sum is 60.

The square root of 7991691819 is about 89396.2628916892. The cubic root of 7991691819 is about 1999.3074117718.

The spelling of 7991691819 in words is "seven billion, nine hundred ninety-one million, six hundred ninety-one thousand, eight hundred nineteen".