81943026813 has 8 divisors (see below), whose sum is σ = 121397076800. Its totient is φ = 54628684524.

The previous prime is 81943026793. The next prime is 81943026887. The reversal of 81943026813 is 31862034918.

It is a de Polignac number, because none of the positive numbers 2^k-81943026813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81943026413) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1517463433 + ... + 1517463486.

It is an arithmetic number, because the mean of its divisors is an integer number (15174634600).

Almost surely, 2^81943026813 is an apocalyptic number.

It is an amenable number.

81943026813 is a deficient number, since it is larger than the sum of its proper divisors (39454049987).

81943026813 is a wasteful number, since it uses less digits than its factorization.

81943026813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3034926928 (or 3034926922 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The spelling of 81943026813 in words is "eighty-one billion, nine hundred forty-three million, twenty-six thousand, eight hundred thirteen".