81122779411 has 4 divisors (see below), whose sum is σ = 85392399400. Its totient is φ = 76853159424.

The previous prime is 81122779393. The next prime is 81122779433. The reversal of 81122779411 is 11497722118.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81122779411 - 2⁵ = 81122779379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81122779511) 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 3 ways as a sum of consecutive naturals, for example, 2134809966 + ... + 2134810003.

It is an arithmetic number, because the mean of its divisors is an integer number (21348099850).

Almost surely, 2^81122779411 is an apocalyptic number.

81122779411 is a deficient number, since it is larger than the sum of its proper divisors (4269619989).

81122779411 is a wasteful number, since it uses less digits than its factorization.

81122779411 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4269619988.

The product of its digits is 56448, while the sum is 43.

The spelling of 81122779411 in words is "eighty-one billion, one hundred twenty-two million, seven hundred seventy-nine thousand, four hundred eleven".