81194906 has 8 divisors (see below), whose sum is σ = 131161044. Its totient is φ = 37474560.

The previous prime is 81194891. The next prime is 81194933. The reversal of 81194906 is 60949118.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 80263681 + 931225 = 8959^2 + 965^2 .

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

It is a super-2 number, since 2×81194906² = 13185225520697672, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81194906.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1561415 + ... + 1561466.

Almost surely, 2^81194906 is an apocalyptic number.

81194906 is a deficient number, since it is larger than the sum of its proper divisors (49966138).

81194906 is a wasteful number, since it uses less digits than its factorization.

81194906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3122896.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 81194906 is about 9010.8216051590. The cubic root of 81194906 is about 433.0216339661.

The spelling of 81194906 in words is "eighty-one million, one hundred ninety-four thousand, nine hundred six".