81981931303 has 4 divisors (see below), whose sum is σ = 82205315680. Its totient is φ = 81758546928.

The previous prime is 81981931279. The next prime is 81981931351. The reversal of 81981931303 is 30313918918.

It is a happy number.

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 81981931303 - 2⁵ = 81981931271 is a prime.

It is a super-2 number, since 2×81981931303² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81981931363) 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, 111691638 + ... + 111692371.

It is an arithmetic number, because the mean of its divisors is an integer number (20551328920).

Almost surely, 2^81981931303 is an apocalyptic number.

81981931303 is a deficient number, since it is larger than the sum of its proper divisors (223384377).

81981931303 is a wasteful number, since it uses less digits than its factorization.

81981931303 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223384376.

The product of its (nonzero) digits is 139968, while the sum is 46.

The spelling of 81981931303 in words is "eighty-one billion, nine hundred eighty-one million, nine hundred thirty-one thousand, three hundred three".