81299278297 has 4 divisors (see below), whose sum is σ = 81459002340. Its totient is φ = 81139554256.

The previous prime is 81299278231. The next prime is 81299278303. The reversal of 81299278297 is 79287299218.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 77117845401 + 4181432896 = 277701^2 + 64664^2 .

It is a cyclic number.

It is not a de Polignac number, because 81299278297 - 2⁷ = 81299278169 is a prime.

It is a super-2 number, since 2×81299278297² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81299278217) 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 3 ways as a sum of consecutive naturals, for example, 79861258 + ... + 79862275.

It is an arithmetic number, because the mean of its divisors is an integer number (20364750585).

Almost surely, 2^81299278297 is an apocalyptic number.

It is an amenable number.

81299278297 is a deficient number, since it is larger than the sum of its proper divisors (159724043).

81299278297 is a wasteful number, since it uses less digits than its factorization.

81299278297 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159724042.

The product of its digits is 18289152, while the sum is 64.

The spelling of 81299278297 in words is "eighty-one billion, two hundred ninety-nine million, two hundred seventy-eight thousand, two hundred ninety-seven".