81238926933 has 12 divisors (see below), whose sum is σ = 117584115168. Its totient is φ = 54048977640.

The previous prime is 81238926893. The next prime is 81238926947. The reversal of 81238926933 is 33962983218.

It is a happy number.

It is not a de Polignac number, because 81238926933 - 2²⁰ = 81237878357 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81238926933.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81238926233) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9187585 + ... + 9196422.

It is an arithmetic number, because the mean of its divisors is an integer number (9798676264).

Almost surely, 2^81238926933 is an apocalyptic number.

It is an amenable number.

81238926933 is a deficient number, since it is larger than the sum of its proper divisors (36345188235).

81238926933 is a wasteful number, since it uses less digits than its factorization.

81238926933 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18384504 (or 18384501 counting only the distinct ones).

The product of its digits is 3359232, while the sum is 54.

The spelling of 81238926933 in words is "eighty-one billion, two hundred thirty-eight million, nine hundred twenty-six thousand, nine hundred thirty-three".