81365761 has 8 divisors (see below), whose sum is σ = 83631680. Its totient is φ = 79116912.

The previous prime is 81365749. The next prime is 81365773. The reversal of 81365761 is 16756318.

It is an interprime number because it is at equal distance from previous prime (81365749) and next prime (81365773).

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 81365761 - 2⁵ = 81365729 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 81365761.

It is not an unprimeable number, because it can be changed into a prime (81365741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5716 + ... + 13978.

It is an arithmetic number, because the mean of its divisors is an integer number (10453960).

Almost surely, 2^81365761 is an apocalyptic number.

It is an amenable number.

81365761 is a deficient number, since it is larger than the sum of its proper divisors (2265919).

81365761 is a wasteful number, since it uses less digits than its factorization.

81365761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8535.

The product of its digits is 30240, while the sum is 37.

The square root of 81365761 is about 9020.2971680538. The cubic root of 81365761 is about 433.3251508646.

The spelling of 81365761 in words is "eighty-one million, three hundred sixty-five thousand, seven hundred sixty-one".