8191809181 has 8 divisors (see below), whose sum is σ = 8258485760. Its totient is φ = 8125243488.

The previous prime is 8191809137. The next prime is 8191809187. The reversal of 8191809181 is 1819081918.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8191809181 is a prime.

It is a super-2 number, since 2×8191809181² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8191809187) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 123985 + ... + 178201.

It is an arithmetic number, because the mean of its divisors is an integer number (1032310720).

Almost surely, 2^8191809181 is an apocalyptic number.

It is an amenable number.

8191809181 is a deficient number, since it is larger than the sum of its proper divisors (66676579).

8191809181 is a wasteful number, since it uses less digits than its factorization.

8191809181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55443.

The product of its (nonzero) digits is 41472, while the sum is 46.

The square root of 8191809181 is about 90508.6138497326. The cubic root of 8191809181 is about 2015.8580275700.

The spelling of 8191809181 in words is "eight billion, one hundred ninety-one million, eight hundred nine thousand, one hundred eighty-one".