81868648109 has 8 divisors (see below), whose sum is σ = 82124766528. Its totient is φ = 81612891360.

The previous prime is 81868648091. The next prime is 81868648129. The reversal of 81868648109 is 90184686818.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81868648109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81868648129) 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 7 ways as a sum of consecutive naturals, for example, 366614 + ... + 546024.

It is an arithmetic number, because the mean of its divisors is an integer number (10265595816).

Almost surely, 2^81868648109 is an apocalyptic number.

It is an amenable number.

81868648109 is a deficient number, since it is larger than the sum of its proper divisors (256118419).

81868648109 is a wasteful number, since it uses less digits than its factorization.

81868648109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180835.

The product of its (nonzero) digits is 5308416, while the sum is 59.

The spelling of 81868648109 in words is "eighty-one billion, eight hundred sixty-eight million, six hundred forty-eight thousand, one hundred nine".