1285515766721 has 8 divisors (see below), whose sum is σ = 1361148168744. Its totient is φ = 1209884901120.

The previous prime is 1285515766693. The next prime is 1285515766747. The reversal of 1285515766721 is 1276675155821.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 48560292496 + 1236955474225 = 220364^2 + 1112185^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1285515766721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1285515766121) 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 in 7 ways as a sum of consecutive naturals, for example, 1644731 + ... + 2296991.

It is an arithmetic number, because the mean of its divisors is an integer number (170143521093).

Almost surely, 2^{1285515766721} is an apocalyptic number.

It is an amenable number.

1285515766721 is a deficient number, since it is larger than the sum of its proper divisors (75632402023).

1285515766721 is a wasteful number, since it uses less digits than its factorization.

1285515766721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 768211.

The product of its digits is 7056000, while the sum is 56.

The spelling of 1285515766721 in words is "one trillion, two hundred eighty-five billion, five hundred fifteen million, seven hundred sixty-six thousand, seven hundred twenty-one".