81364877846249 has 2 divisors, whose sum is σ = 81364877846250. Its totient is φ = 81364877846248.

The previous prime is 81364877846243. The next prime is 81364877846279. The reversal of 81364877846249 is 94264877846318.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81014760672400 + 350117173849 = 9000820^2 + 591707^2 .

It is a cyclic number.

It is not a de Polignac number, because 81364877846249 - 2³⁶ = 81296158369513 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81364877846249.

It is not a weakly prime, because it can be changed into another prime (81364877846243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40682438923124 + 40682438923125.

It is an arithmetic number, because the mean of its divisors is an integer number (40682438923125).

Almost surely, 2^{81364877846249} is an apocalyptic number.

It is an amenable number.

81364877846249 is a deficient number, since it is larger than the sum of its proper divisors (1).

81364877846249 is an equidigital number, since it uses as much as digits as its factorization.

81364877846249 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3121348608, while the sum is 77.

The spelling of 81364877846249 in words is "eighty-one trillion, three hundred sixty-four billion, eight hundred seventy-seven million, eight hundred forty-six thousand, two hundred forty-nine".