81566287 has 8 divisors (see below), whose sum is σ = 89863632. Its totient is φ = 73416000.

The previous prime is 81566267. The next prime is 81566327. The reversal of 81566287 is 78266518.

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 81566287 - 2²³ = 73177679 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81566267) 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, 35598 + ... + 37819.

It is an arithmetic number, because the mean of its divisors is an integer number (11232954).

Almost surely, 2^81566287 is an apocalyptic number.

81566287 is a deficient number, since it is larger than the sum of its proper divisors (8297345).

81566287 is a wasteful number, since it uses less digits than its factorization.

81566287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73529.

The product of its digits is 161280, while the sum is 43.

The square root of 81566287 is about 9031.4055938154. The cubic root of 81566287 is about 433.6808355863.

The spelling of 81566287 in words is "eighty-one million, five hundred sixty-six thousand, two hundred eighty-seven".