1287517457081 has 4 divisors (see below), whose sum is σ = 1287535982964. Its totient is φ = 1287498931200.

The previous prime is 1287517457071. The next prime is 1287517457089. The reversal of 1287517457081 is 1807547157821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 882237525625 + 405279931456 = 939275^2 + 636616^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1287517457081 is a prime.

It is a super-2 number, since 2×1287517457081² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1287517457089) 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 in 3 ways as a sum of consecutive naturals, for example, 9158300 + ... + 9297821.

It is an arithmetic number, because the mean of its divisors is an integer number (321883995741).

Almost surely, 2^{1287517457081} is an apocalyptic number.

It is an amenable number.

1287517457081 is a deficient number, since it is larger than the sum of its proper divisors (18525883).

1287517457081 is an equidigital number, since it uses as much as digits as its factorization.

1287517457081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18525882.

The product of its (nonzero) digits is 4390400, while the sum is 56.

The spelling of 1287517457081 in words is "one trillion, two hundred eighty-seven billion, five hundred seventeen million, four hundred fifty-seven thousand, eighty-one".