81329528085 has 32 divisors (see below), whose sum is σ = 140161650048. Its totient is φ = 40032119040.

The previous prime is 81329528083. The next prime is 81329528087. The reversal of 81329528085 is 58082592318.

It is an interprime number because it is at equal distance from previous prime (81329528083) and next prime (81329528087).

It is not a de Polignac number, because 81329528085 - 2¹ = 81329528083 is a prime.

It is a super-2 number, since 2×81329528085² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81329528083) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1179574 + ... + 1246616.

It is an arithmetic number, because the mean of its divisors is an integer number (4380051564).

Almost surely, 2^81329528085 is an apocalyptic number.

It is an amenable number.

81329528085 is a deficient number, since it is larger than the sum of its proper divisors (58832121963).

81329528085 is a wasteful number, since it uses less digits than its factorization.

81329528085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73285.

The product of its (nonzero) digits is 1382400, while the sum is 51.

The spelling of 81329528085 in words is "eighty-one billion, three hundred twenty-nine million, five hundred twenty-eight thousand, eighty-five".