81384565 has 16 divisors (see below), whose sum is σ = 99535680. Its totient is φ = 63866880.

The previous prime is 81384533. The next prime is 81384577. The reversal of 81384565 is 56548318.

It is not a de Polignac number, because 81384565 - 2⁵ = 81384533 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 126645 + ... + 127285.

It is an arithmetic number, because the mean of its divisors is an integer number (6220980).

Almost surely, 2^81384565 is an apocalyptic number.

It is an amenable number.

81384565 is a deficient number, since it is larger than the sum of its proper divisors (18151115).

81384565 is a wasteful number, since it uses less digits than its factorization.

81384565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1092.

The product of its digits is 115200, while the sum is 40.

The square root of 81384565 is about 9021.3394238328. The cubic root of 81384565 is about 433.3585294357.

The spelling of 81384565 in words is "eighty-one million, three hundred eighty-four thousand, five hundred sixty-five".