81322335261 has 64 divisors (see below), whose sum is σ = 129436876800. Its totient is φ = 50329781568.

The previous prime is 81322335239. The next prime is 81322335293. The reversal of 81322335261 is 16253322318.

81322335261 is a `hidden beast` number, since 81 + 3 + 22 + 33 + 526 + 1 = 666.

It is not a de Polignac number, because 81322335261 - 2⁵ = 81322335229 is a prime.

It is a super-2 number, since 2×81322335261² (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 (81322335361) 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 63 ways as a sum of consecutive naturals, for example, 9623140 + ... + 9631586.

It is an arithmetic number, because the mean of its divisors is an integer number (2022451200).

Almost surely, 2^81322335261 is an apocalyptic number.

It is an amenable number.

81322335261 is a deficient number, since it is larger than the sum of its proper divisors (48114541539).

81322335261 is a wasteful number, since it uses less digits than its factorization.

81322335261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8935 (or 8929 counting only the distinct ones).

The product of its digits is 51840, while the sum is 36.

Adding to 81322335261 its reverse (16253322318), we get a palindrome (97575657579).

The spelling of 81322335261 in words is "eighty-one billion, three hundred twenty-two million, three hundred thirty-five thousand, two hundred sixty-one".