81291916051 has 8 divisors (see below), whose sum is σ = 84111667200. Its totient is φ = 78473270400.

The previous prime is 81291916039. The next prime is 81291916087. The reversal of 81291916051 is 15061919218.

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 81291916051 - 2⁹ = 81291915539 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81291915989 and 81291916007.

It is not an unprimeable number, because it can be changed into a prime (81291913051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 125350 + ... + 422251.

It is an arithmetic number, because the mean of its divisors is an integer number (10513958400).

Almost surely, 2^81291916051 is an apocalyptic number.

81291916051 is a deficient number, since it is larger than the sum of its proper divisors (2819751149).

81291916051 is a wasteful number, since it uses less digits than its factorization.

81291916051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 552749.

The product of its (nonzero) digits is 38880, while the sum is 43.

The spelling of 81291916051 in words is "eighty-one billion, two hundred ninety-one million, nine hundred sixteen thousand, fifty-one".