81732920245 has 8 divisors (see below), whose sum is σ = 98979316920. Its totient is φ = 64786461120.

The previous prime is 81732920237. The next prime is 81732920249. The reversal of 81732920245 is 54202923718.

It can be written as a sum of positive squares in 4 ways, for example, as 5224253841 + 76508666404 = 72279^2 + 276602^2 .

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

It is not a de Polignac number, because 81732920245 - 2³ = 81732920237 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81732920249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 74983786 + ... + 74984875.

It is an arithmetic number, because the mean of its divisors is an integer number (12372414615).

Almost surely, 2^81732920245 is an apocalyptic number.

It is an amenable number.

81732920245 is a deficient number, since it is larger than the sum of its proper divisors (17246396675).

81732920245 is a wasteful number, since it uses less digits than its factorization.

81732920245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149968775.

The product of its (nonzero) digits is 241920, while the sum is 43.

The spelling of 81732920245 in words is "eighty-one billion, seven hundred thirty-two million, nine hundred twenty thousand, two hundred forty-five".