81377247673 has 2 divisors, whose sum is σ = 81377247674. Its totient is φ = 81377247672.

The previous prime is 81377247671. The next prime is 81377247689. The reversal of 81377247673 is 37674277318.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77079527424 + 4297720249 = 277632^2 + 65557^2 .

It is a cyclic number.

It is not a de Polignac number, because 81377247673 - 2¹ = 81377247671 is a prime.

Together with 81377247671, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (81377247671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40688623836 + 40688623837.

It is an arithmetic number, because the mean of its divisors is an integer number (40688623837).

Almost surely, 2^81377247673 is an apocalyptic number.

It is an amenable number.

81377247673 is a deficient number, since it is larger than the sum of its proper divisors (1).

81377247673 is an equidigital number, since it uses as much as digits as its factorization.

81377247673 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8297856, while the sum is 55.

The spelling of 81377247673 in words is "eighty-one billion, three hundred seventy-seven million, two hundred forty-seven thousand, six hundred seventy-three".