81211711711 has 8 divisors (see below), whose sum is σ = 87565046240. Its totient is φ = 74873560032.

The previous prime is 81211711709. The next prime is 81211711733. The reversal of 81211711711 is 11711711218.

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 81211711711 - 2¹ = 81211711709 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 (81211711771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3784596 + ... + 3805993.

It is an arithmetic number, because the mean of its divisors is an integer number (10945630780).

Almost surely, 2^81211711711 is an apocalyptic number.

81211711711 is a deficient number, since it is larger than the sum of its proper divisors (6353334529).

81211711711 is a wasteful number, since it uses less digits than its factorization.

81211711711 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7591425.

The product of its digits is 784, while the sum is 31.

The spelling of 81211711711 in words is "eighty-one billion, two hundred eleven million, seven hundred eleven thousand, seven hundred eleven".