81365651 has 8 divisors (see below), whose sum is σ = 85100064. Its totient is φ = 77647680.

The previous prime is 81365623. The next prime is 81365659. The reversal of 81365651 is 15656318.

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 81365651 - 2¹⁰ = 81364627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81365659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6641 + ... + 14381.

It is an arithmetic number, because the mean of its divisors is an integer number (10637508).

Almost surely, 2^81365651 is an apocalyptic number.

81365651 is a deficient number, since it is larger than the sum of its proper divisors (3734413).

81365651 is a wasteful number, since it uses less digits than its factorization.

81365651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8221.

The product of its digits is 21600, while the sum is 35.

The square root of 81365651 is about 9020.2910706917. The cubic root of 81365651 is about 433.3249555908.

The spelling of 81365651 in words is "eighty-one million, three hundred sixty-five thousand, six hundred fifty-one".