81783118964 has 6 divisors (see below), whose sum is σ = 143120458194. Its totient is φ = 40891559480.

The previous prime is 81783118943. The next prime is 81783119003. The reversal of 81783118964 is 46981138718.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 56958595600 + 24824523364 = 238660^2 + 157558^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10222889867 + ... + 10222889874.

It is an arithmetic number, because the mean of its divisors is an integer number (23853409699).

Almost surely, 2^81783118964 is an apocalyptic number.

It is an amenable number.

81783118964 is a deficient number, since it is larger than the sum of its proper divisors (61337339230).

81783118964 is a wasteful number, since it uses less digits than its factorization.

81783118964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20445779745 (or 20445779743 counting only the distinct ones).

The product of its digits is 2322432, while the sum is 56.

The spelling of 81783118964 in words is "eighty-one billion, seven hundred eighty-three million, one hundred eighteen thousand, nine hundred sixty-four".