81911254471 has 2 divisors, whose sum is σ = 81911254472. Its totient is φ = 81911254470.

The previous prime is 81911254463. The next prime is 81911254507. The reversal of 81911254471 is 17445211918.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81911254471 - 2³ = 81911254463 is a prime.

It is a super-3 number, since 3×81911254471³ (a number of 34 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81911254421) 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 as a sum of consecutive naturals, namely, 40955627235 + 40955627236.

It is an arithmetic number, because the mean of its divisors is an integer number (40955627236).

Almost surely, 2^81911254471 is an apocalyptic number.

81911254471 is a deficient number, since it is larger than the sum of its proper divisors (1).

81911254471 is an equidigital number, since it uses as much as digits as its factorization.

81911254471 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 80640, while the sum is 43.

The spelling of 81911254471 in words is "eighty-one billion, nine hundred eleven million, two hundred fifty-four thousand, four hundred seventy-one".