81984563613 has 16 divisors (see below), whose sum is σ = 128603237760. Its totient is φ = 51441294528.

The previous prime is 81984563603. The next prime is 81984563671. The reversal of 81984563613 is 31636548918.

81984563613 is a `hidden beast` number, since 8 + 19 + 8 + 4 + 5 + 6 + 3 + 613 = 666.

It is not a de Polignac number, because 81984563613 - 2⁴ = 81984563597 is a prime.

It is a super-2 number, since 2×81984563613² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81984563613.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81984563603) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 89307345 + ... + 89308262.

It is an arithmetic number, because the mean of its divisors is an integer number (8037702360).

Almost surely, 2^81984563613 is an apocalyptic number.

It is an amenable number.

81984563613 is a deficient number, since it is larger than the sum of its proper divisors (46618674147).

81984563613 is a wasteful number, since it uses less digits than its factorization.

81984563613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178615633 (or 178615627 counting only the distinct ones).

The product of its digits is 3732480, while the sum is 54.

The spelling of 81984563613 in words is "eighty-one billion, nine hundred eighty-four million, five hundred sixty-three thousand, six hundred thirteen".