81933809844 has 48 divisors (see below), whose sum is σ = 199380532736. Its totient is φ = 26157772800.

The previous prime is 81933809833. The next prime is 81933809849. The reversal of 81933809844 is 44890833918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81933809849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1099237 + ... + 1171404.

Almost surely, 2^81933809844 is an apocalyptic number.

It is an amenable number.

81933809844 is an abundant number, since it is smaller than the sum of its proper divisors (117446722892).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81933809844 is a wasteful number, since it uses less digits than its factorization.

81933809844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2270776 (or 2270774 counting only the distinct ones).

The product of its (nonzero) digits is 5971968, while the sum is 57.

The spelling of 81933809844 in words is "eighty-one billion, nine hundred thirty-three million, eight hundred nine thousand, eight hundred forty-four".