81534565 has 8 divisors (see below), whose sum is σ = 111818880. Its totient is φ = 55909392.

The previous prime is 81534553. The next prime is 81534641. The reversal of 81534565 is 56543518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81534565 - 2⁷ = 81534437 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1164745 + ... + 1164814.

It is an arithmetic number, because the mean of its divisors is an integer number (13977360).

Almost surely, 2^81534565 is an apocalyptic number.

It is an amenable number.

81534565 is a deficient number, since it is larger than the sum of its proper divisors (30284315).

81534565 is a wasteful number, since it uses less digits than its factorization.

81534565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2329571.

The product of its digits is 72000, while the sum is 37.

The square root of 81534565 is about 9029.6492179929. The cubic root of 81534565 is about 433.6246072604.

The spelling of 81534565 in words is "eighty-one million, five hundred thirty-four thousand, five hundred sixty-five".