81322756287 has 4 divisors (see below), whose sum is σ = 108430341720. Its totient is φ = 54215170856.

The previous prime is 81322756199. The next prime is 81322756303. The reversal of 81322756287 is 78265722318.

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

It is a cyclic number.

It is not a de Polignac number, because 81322756287 - 2¹² = 81322752191 is a prime.

It is a super-2 number, since 2×81322756287² (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 (81322756187) 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 3 ways as a sum of consecutive naturals, for example, 13553792712 + ... + 13553792717.

It is an arithmetic number, because the mean of its divisors is an integer number (27107585430).

Almost surely, 2^81322756287 is an apocalyptic number.

81322756287 is a deficient number, since it is larger than the sum of its proper divisors (27107585433).

81322756287 is a wasteful number, since it uses less digits than its factorization.

81322756287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27107585432.

The product of its digits is 2257920, while the sum is 51.

The spelling of 81322756287 in words is "eighty-one billion, three hundred twenty-two million, seven hundred fifty-six thousand, two hundred eighty-seven".