81707565 has 8 divisors (see below), whose sum is σ = 130732128. Its totient is φ = 43577360.

The previous prime is 81707557. The next prime is 81707579. The reversal of 81707565 is 56570718.

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

It is not a de Polignac number, because 81707565 - 2³ = 81707557 is a prime.

It is a super-2 number, since 2×81707565² = 13352252356458450, which contains 22 as substring.

It is a plaindrome in base 12.

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, 2723571 + ... + 2723600.

It is an arithmetic number, because the mean of its divisors is an integer number (16341516).

Almost surely, 2^81707565 is an apocalyptic number.

It is an amenable number.

81707565 is a deficient number, since it is larger than the sum of its proper divisors (49024563).

81707565 is a wasteful number, since it uses less digits than its factorization.

81707565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5447179.

The product of its (nonzero) digits is 58800, while the sum is 39.

The square root of 81707565 is about 9039.2236945437. The cubic root of 81707565 is about 433.9310787651.

The spelling of 81707565 in words is "eighty-one million, seven hundred seven thousand, five hundred sixty-five".