81916805697 has 16 divisors (see below), whose sum is σ = 111465087552. Its totient is φ = 53498871360.

The previous prime is 81916805687. The next prime is 81916805723. The reversal of 81916805697 is 79650861918.

It is not a de Polignac number, because 81916805697 - 2¹¹ = 81916803649 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81916805697.

It is not an unprimeable number, because it can be changed into a prime (81916805627) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1089438 + ... + 1162199.

It is an arithmetic number, because the mean of its divisors is an integer number (6966567972).

Almost surely, 2^81916805697 is an apocalyptic number.

It is an amenable number.

81916805697 is a deficient number, since it is larger than the sum of its proper divisors (29548281855).

81916805697 is a wasteful number, since it uses less digits than its factorization.

81916805697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2251888.

The product of its (nonzero) digits is 6531840, while the sum is 60.

The spelling of 81916805697 in words is "eighty-one billion, nine hundred sixteen million, eight hundred five thousand, six hundred ninety-seven".