81377422717 has 2 divisors, whose sum is σ = 81377422718. Its totient is φ = 81377422716.

The previous prime is 81377422703. The next prime is 81377422739. The reversal of 81377422717 is 71722477318.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 79475503396 + 1901919321 = 281914^2 + 43611^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81377422717 is a prime.

It is a super-2 number, since 2×81377422717² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81377422517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40688711358 + 40688711359.

It is an arithmetic number, because the mean of its divisors is an integer number (40688711359).

Almost surely, 2^81377422717 is an apocalyptic number.

It is an amenable number.

81377422717 is a deficient number, since it is larger than the sum of its proper divisors (1).

81377422717 is an equidigital number, since it uses as much as digits as its factorization.

81377422717 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 921984, while the sum is 49.

The spelling of 81377422717 in words is "eighty-one billion, three hundred seventy-seven million, four hundred twenty-two thousand, seven hundred seventeen".