81396660601 has 3 divisors (see below), whose sum is σ = 81396945903. Its totient is φ = 81396375300.

The previous prime is 81396660517. The next prime is 81396660613. The reversal of 81396660601 is 10606669318.

The square root of 81396660601 is 285301.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 50512113001 + 30884547600 = 224749^2 + 175740^2 .

It is not a de Polignac number, because 81396660601 - 2¹⁹ = 81396136313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81396660691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 142651 + ... + 427951.

It is an arithmetic number, because the mean of its divisors is an integer number (27132315301).

Almost surely, 2^81396660601 is an apocalyptic number.

81396660601 is the 285301-st square number.

81396660601 is the 142651-st centered octagonal number.

It is an amenable number.

81396660601 is a deficient number, since it is larger than the sum of its proper divisors (285302).

81396660601 is an frugal number, since it uses more digits than its factorization.

81396660601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 570602 (or 285301 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 46.

The spelling of 81396660601 in words is "eighty-one billion, three hundred ninety-six million, six hundred sixty thousand, six hundred one".