81186492349 has 4 divisors (see below), whose sum is σ = 81198315040. Its totient is φ = 81174669660.

The previous prime is 81186492329. The next prime is 81186492367. The reversal of 81186492349 is 94329468118.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81186492349 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81186492349.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81186492329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5901039 + ... + 5914780.

It is an arithmetic number, because the mean of its divisors is an integer number (20299578760).

Almost surely, 2^81186492349 is an apocalyptic number.

It is an amenable number.

81186492349 is a deficient number, since it is larger than the sum of its proper divisors (11822691).

81186492349 is a wasteful number, since it uses less digits than its factorization.

81186492349 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11822690.

The product of its digits is 2985984, while the sum is 55.

The spelling of 81186492349 in words is "eighty-one billion, one hundred eighty-six million, four hundred ninety-two thousand, three hundred forty-nine".