81869788796819 has 4 divisors (see below), whose sum is σ = 81870173915040. Its totient is φ = 81869403678600.

The previous prime is 81869788796801. The next prime is 81869788796827. The reversal of 81869788796819 is 91869788796818.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81869788796819 - 2⁴⁴ = 64277602752403 is a prime.

It is a super-2 number, since 2×81869788796819² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81869788796849) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 192240059 + ... + 192665460.

It is an arithmetic number, because the mean of its divisors is an integer number (20467543478760).

Almost surely, 2^{81869788796819} is an apocalyptic number.

81869788796819 is a deficient number, since it is larger than the sum of its proper divisors (385118221).

81869788796819 is a wasteful number, since it uses less digits than its factorization.

81869788796819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385118220.

The product of its digits is 42138206208, while the sum is 95.

Subtracting 81869788796819 from its reverse (91869788796818), we obtain a palindrome (9999999999999).

The spelling of 81869788796819 in words is "eighty-one trillion, eight hundred sixty-nine billion, seven hundred eighty-eight million, seven hundred ninety-six thousand, eight hundred nineteen".