81324563784 has 16 divisors (see below), whose sum is σ = 203311409520. Its totient is φ = 27108187920.

The previous prime is 81324563767. The next prime is 81324563797. The reversal of 81324563784 is 48736542318.

It is a happy number.

It is a super-2 number, since 2×81324563784² (a number of 23 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (51) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1694261722 + ... + 1694261769.

It is an arithmetic number, because the mean of its divisors is an integer number (12706963095).

Almost surely, 2^81324563784 is an apocalyptic number.

It is an amenable number.

81324563784 is an abundant number, since it is smaller than the sum of its proper divisors (121986845736).

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

81324563784 is a wasteful number, since it uses less digits than its factorization.

81324563784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3388523500 (or 3388523496 counting only the distinct ones).

The product of its digits is 3870720, while the sum is 51.

The spelling of 81324563784 in words is "eighty-one billion, three hundred twenty-four million, five hundred sixty-three thousand, seven hundred eighty-four".