81711354973 has 4 divisors (see below), whose sum is σ = 81906370560. Its totient is φ = 81516339388.

The previous prime is 81711354937. The next prime is 81711354979. The reversal of 81711354973 is 37945311718.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 37945311718 = 2 ⋅18972655859.

It is a cyclic number.

It is not a de Polignac number, because 81711354973 - 2²⁵ = 81677800541 is a prime.

It is a super-2 number, since 2×81711354973² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81711354979) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 97507165 + ... + 97508002.

It is an arithmetic number, because the mean of its divisors is an integer number (20476592640).

Almost surely, 2^81711354973 is an apocalyptic number.

It is an amenable number.

81711354973 is a deficient number, since it is larger than the sum of its proper divisors (195015587).

81711354973 is a wasteful number, since it uses less digits than its factorization.

81711354973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195015586.

The product of its digits is 635040, while the sum is 49.

The spelling of 81711354973 in words is "eighty-one billion, seven hundred eleven million, three hundred fifty-four thousand, nine hundred seventy-three".