81049393189 has 4 divisors (see below), whose sum is σ = 81175442656. Its totient is φ = 80923343724.

The previous prime is 81049393177. The next prime is 81049393237. The reversal of 81049393189 is 98139394018.

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 not a de Polignac number, because 81049393189 - 2¹¹ = 81049391141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81049393289) 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, 63023769 + ... + 63025054.

It is an arithmetic number, because the mean of its divisors is an integer number (20293860664).

Almost surely, 2^81049393189 is an apocalyptic number.

It is an amenable number.

81049393189 is a deficient number, since it is larger than the sum of its proper divisors (126049467).

81049393189 is a wasteful number, since it uses less digits than its factorization.

81049393189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126049466.

The product of its (nonzero) digits is 1679616, while the sum is 55.

The spelling of 81049393189 in words is "eighty-one billion, forty-nine million, three hundred ninety-three thousand, one hundred eighty-nine".