81194775 has 12 divisors (see below), whose sum is σ = 134242152. Its totient is φ = 43303840.

The previous prime is 81194759. The next prime is 81194777. The reversal of 81194775 is 57749118.

It is not a de Polignac number, because 81194775 - 2⁴ = 81194759 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81194777) 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 11 ways as a sum of consecutive naturals, for example, 541224 + ... + 541373.

It is an arithmetic number, because the mean of its divisors is an integer number (11186846).

Almost surely, 2^81194775 is an apocalyptic number.

81194775 is a deficient number, since it is larger than the sum of its proper divisors (53047377).

81194775 is a wasteful number, since it uses less digits than its factorization.

81194775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1082610 (or 1082605 counting only the distinct ones).

The product of its digits is 70560, while the sum is 42.

The square root of 81194775 is about 9010.8143361186. The cubic root of 81194775 is about 433.0214010867.

The spelling of 81194775 in words is "eighty-one million, one hundred ninety-four thousand, seven hundred seventy-five".