81788212047 has 4 divisors (see below), whose sum is σ = 109050949400. Its totient is φ = 54525474696.

The previous prime is 81788212043. The next prime is 81788212063. The reversal of 81788212047 is 74021288718.

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

It is not a de Polignac number, because 81788212047 - 2² = 81788212043 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81788211987 and 81788212005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81788212043) by changing a digit.

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, 13631368672 + ... + 13631368677.

It is an arithmetic number, because the mean of its divisors is an integer number (27262737350).

Almost surely, 2^81788212047 is an apocalyptic number.

81788212047 is a deficient number, since it is larger than the sum of its proper divisors (27262737353).

81788212047 is a wasteful number, since it uses less digits than its factorization.

81788212047 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27262737352.

The product of its (nonzero) digits is 401408, while the sum is 48.

The spelling of 81788212047 in words is "eighty-one billion, seven hundred eighty-eight million, two hundred twelve thousand, forty-seven".