81522575165 has 8 divisors (see below), whose sum is σ = 99167187768. Its totient is φ = 64324661760.

The previous prime is 81522575137. The next prime is 81522575171. The reversal of 81522575165 is 56157522518.

It can be written as a sum of positive squares in 4 ways, for example, as 5314555801 + 76208019364 = 72901^2 + 276058^2 .

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

It is not a de Polignac number, because 81522575165 - 2⁸ = 81522574909 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, 111674396 + ... + 111675125.

It is an arithmetic number, because the mean of its divisors is an integer number (12395898471).

Almost surely, 2^81522575165 is an apocalyptic number.

It is an amenable number.

81522575165 is a deficient number, since it is larger than the sum of its proper divisors (17644612603).

81522575165 is a wasteful number, since it uses less digits than its factorization.

81522575165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223349599.

The product of its digits is 840000, while the sum is 47.

The spelling of 81522575165 in words is "eighty-one billion, five hundred twenty-two million, five hundred seventy-five thousand, one hundred sixty-five".