81017971955 has 8 divisors (see below), whose sum is σ = 97352420832. Its totient is φ = 64727141248.

The previous prime is 81017971933. The next prime is 81017971963. The reversal of 81017971955 is 55917971018.

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 81017971955 - 2¹⁰ = 81017970931 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81017971897 and 81017971906.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10900454 + ... + 10907883.

It is an arithmetic number, because the mean of its divisors is an integer number (12169052604).

Almost surely, 2^81017971955 is an apocalyptic number.

81017971955 is a deficient number, since it is larger than the sum of its proper divisors (16334448877).

81017971955 is a wasteful number, since it uses less digits than its factorization.

81017971955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21809085.

The product of its (nonzero) digits is 793800, while the sum is 53.

The spelling of 81017971955 in words is "eighty-one billion, seventeen million, nine hundred seventy-one thousand, nine hundred fifty-five".