81766799 has 4 divisors (see below), whose sum is σ = 82062264. Its totient is φ = 81471336.

The previous prime is 81766777. The next prime is 81766801. The reversal of 81766799 is 99766718.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81766799 - 2⁸ = 81766543 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 81766799.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81766739) 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 3 ways as a sum of consecutive naturals, for example, 147317 + ... + 147870.

It is an arithmetic number, because the mean of its divisors is an integer number (20515566).

Almost surely, 2^81766799 is an apocalyptic number.

81766799 is a deficient number, since it is larger than the sum of its proper divisors (295465).

81766799 is a wasteful number, since it uses less digits than its factorization.

81766799 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295464.

The product of its digits is 1143072, while the sum is 53.

The square root of 81766799 is about 9042.4995991153. The cubic root of 81766799 is about 434.0359130595.

The spelling of 81766799 in words is "eighty-one million, seven hundred sixty-six thousand, seven hundred ninety-nine".