81788221105 has 8 divisors (see below), whose sum is σ = 98156132712. Its totient is φ = 65423731968.

The previous prime is 81788221087. The next prime is 81788221121. The reversal of 81788221105 is 50112288718.

It can be written as a sum of positive squares in 4 ways, for example, as 47560631056 + 34227590049 = 218084^2 + 185007^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81788221105 - 2⁷ = 81788220977 is a prime.

It is a super-2 number, since 2×81788221105² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

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 7 ways as a sum of consecutive naturals, for example, 802744 + ... + 898873.

It is an arithmetic number, because the mean of its divisors is an integer number (12269516589).

Almost surely, 2^81788221105 is an apocalyptic number.

It is an amenable number.

81788221105 is a deficient number, since it is larger than the sum of its proper divisors (16367911607).

81788221105 is a wasteful number, since it uses less digits than its factorization.

81788221105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1711235.

The product of its (nonzero) digits is 71680, while the sum is 43.

The spelling of 81788221105 in words is "eighty-one billion, seven hundred eighty-eight million, two hundred twenty-one thousand, one hundred five".