81091306933 has 16 divisors (see below), whose sum is σ = 101171881216. Its totient is φ = 63281243520.

The previous prime is 81091306913. The next prime is 81091306939. The reversal of 81091306933 is 33960319018.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 81091306933 - 2¹³ = 81091298741 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81091306933.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81091306939) 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 15 ways as a sum of consecutive naturals, for example, 6096873 + ... + 6110158.

It is an arithmetic number, because the mean of its divisors is an integer number (6323242576).

Almost surely, 2^81091306933 is an apocalyptic number.

It is an amenable number.

81091306933 is a deficient number, since it is larger than the sum of its proper divisors (20080574283).

81091306933 is a wasteful number, since it uses less digits than its factorization.

81091306933 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12207124.

The product of its (nonzero) digits is 104976, while the sum is 43.

The spelling of 81091306933 in words is "eighty-one billion, ninety-one million, three hundred six thousand, nine hundred thirty-three".