81597165 has 16 divisors (see below), whose sum is σ = 140598528. Its totient is φ = 40170816.

The previous prime is 81597151. The next prime is 81597167. The reversal of 81597165 is 56179518.

It is not a de Polignac number, because 81597165 - 2¹⁶ = 81531629 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81597167) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 209029 + ... + 209418.

It is an arithmetic number, because the mean of its divisors is an integer number (8787408).

Almost surely, 2^81597165 is an apocalyptic number.

It is an amenable number.

81597165 is a deficient number, since it is larger than the sum of its proper divisors (59001363).

81597165 is a wasteful number, since it uses less digits than its factorization.

81597165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 418468.

The product of its digits is 75600, while the sum is 42.

The square root of 81597165 is about 9033.1149112585. The cubic root of 81597165 is about 433.7355538933.

The spelling of 81597165 in words is "eighty-one million, five hundred ninety-seven thousand, one hundred sixty-five".