81766081 has 8 divisors (see below), whose sum is σ = 85702464. Its totient is φ = 77861520.

The previous prime is 81766079. The next prime is 81766099. The reversal of 81766081 is 18066718.

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 81766081 - 2¹ = 81766079 is a prime.

It is a super-2 number, since 2×81766081² = 13371384004197122, which contains 22 as substring.

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 81766081.

It is not an unprimeable number, because it can be changed into a prime (81766001) 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, 2610 + ... + 13051.

It is an arithmetic number, because the mean of its divisors is an integer number (10712808).

Almost surely, 2^81766081 is an apocalyptic number.

81766081 is the 5221-st octagonal number.

It is an amenable number.

81766081 is a deficient number, since it is larger than the sum of its proper divisors (3936383).

81766081 is a wasteful number, since it uses less digits than its factorization.

81766081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15911.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 81766081 is about 9042.4598976164. The cubic root of 81766081 is about 434.0346426225.

The spelling of 81766081 in words is "eighty-one million, seven hundred sixty-six thousand, eighty-one".