81766199 has 8 divisors (see below), whose sum is σ = 82340640. Its totient is φ = 81194400.

The previous prime is 81766159. The next prime is 81766211. The reversal of 81766199 is 99166718.

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

It is a cyclic number.

It is not a de Polignac number, because 81766199 - 2¹² = 81762103 is a prime.

It is a super-2 number, since 2×81766199² = 13371422597815202, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81766159) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 150869 + ... + 151409.

It is an arithmetic number, because the mean of its divisors is an integer number (10292580).

Almost surely, 2^81766199 is an apocalyptic number.

81766199 is a deficient number, since it is larger than the sum of its proper divisors (574441).

81766199 is a wasteful number, since it uses less digits than its factorization.

81766199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1321.

The product of its digits is 163296, while the sum is 47.

The square root of 81766199 is about 9042.4664223872. The cubic root of 81766199 is about 434.0348514135.

The spelling of 81766199 in words is "eighty-one million, seven hundred sixty-six thousand, one hundred ninety-nine".