81106192197 has 6 divisors (see below), whose sum is σ = 117153388742. Its totient is φ = 54070794792.

The previous prime is 81106192187. The next prime is 81106192207. The reversal of 81106192197 is 79129160118.

It is a happy number.

81106192197 is a `hidden beast` number, since 8 + 1 + 1 + 0 + 619 + 21 + 9 + 7 = 666.

It is an interprime number because it is at equal distance from previous prime (81106192187) and next prime (81106192207).

It can be written as a sum of positive squares in only one way, i.e., 52205852196 + 28900340001 = 228486^2 + 170001^2 .

It is not a de Polignac number, because 81106192197 - 2²⁴ = 81089414981 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 (81106192147) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4505899558 + ... + 4505899575.

Almost surely, 2^81106192197 is an apocalyptic number.

It is an amenable number.

81106192197 is a deficient number, since it is larger than the sum of its proper divisors (36047196545).

81106192197 is a wasteful number, since it uses less digits than its factorization.

81106192197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9011799139 (or 9011799136 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 45.

The spelling of 81106192197 in words is "eighty-one billion, one hundred six million, one hundred ninety-two thousand, one hundred ninety-seven".