81567565 has 8 divisors (see below), whose sum is σ = 97982208. Its totient is φ = 65186640.

The previous prime is 81567539. The next prime is 81567571. The reversal of 81567565 is 56576518.

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

It is not a de Polignac number, because 81567565 - 2¹⁵ = 81534797 is a prime.

It is a Duffinian number.

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, 2757 + ... + 13066.

It is an arithmetic number, because the mean of its divisors is an integer number (12247776).

Almost surely, 2^81567565 is an apocalyptic number.

It is an amenable number.

81567565 is a deficient number, since it is larger than the sum of its proper divisors (16414643).

81567565 is a wasteful number, since it uses less digits than its factorization.

81567565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16859.

The product of its digits is 252000, while the sum is 43.

The square root of 81567565 is about 9031.4763466446. The cubic root of 81567565 is about 433.6831005793.

The spelling of 81567565 in words is "eighty-one million, five hundred sixty-seven thousand, five hundred sixty-five".