81381255077 has 2 divisors, whose sum is σ = 81381255078. Its totient is φ = 81381255076.

The previous prime is 81381255013. The next prime is 81381255083. The reversal of 81381255077 is 77055218318.

It is a happy number.

It is a Cunningham number, because it is equal to 285274²+1.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81381255076 + 1 = 285274^2 + 1^2 .

It is a cyclic number.

It is not a de Polignac number, because 81381255077 - 2⁶ = 81381255013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81381285077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40690627538 + 40690627539.

It is an arithmetic number, because the mean of its divisors is an integer number (40690627539).

Almost surely, 2^81381255077 is an apocalyptic number.

It is an amenable number.

81381255077 is a deficient number, since it is larger than the sum of its proper divisors (1).

81381255077 is an equidigital number, since it uses as much as digits as its factorization.

81381255077 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 470400, while the sum is 47.

The spelling of 81381255077 in words is "eighty-one billion, three hundred eighty-one million, two hundred fifty-five thousand, seventy-seven".