81814768777728 has 120 divisors (see below), whose sum is σ = 269854814088288. Its totient is φ = 23375648212992.

The previous prime is 81814768777727. The next prime is 81814768777741. The reversal of 81814768777728 is 82777786741818.

81814768777728 is a `hidden beast` number, since 8 + 1 + 8 + 1 + 476 + 8 + 7 + 77 + 72 + 8 = 666.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (81814768777727) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1268177826 + ... + 1268242337.

Almost surely, 2^{81814768777728} is an apocalyptic number.

It is an amenable number.

81814768777728 is an abundant number, since it is smaller than the sum of its proper divisors (188040045310560).

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

81814768777728 is a wasteful number, since it uses less digits than its factorization.

81814768777728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2536420194 (or 2536420175 counting only the distinct ones).

The product of its digits is 3304390656, while the sum is 81.

The spelling of 81814768777728 in words is "eighty-one trillion, eight hundred fourteen billion, seven hundred sixty-eight million, seven hundred seventy-seven thousand, seven hundred twenty-eight".