768816561 has 16 divisors (see below), whose sum is σ = 1070481024. Its totient is φ = 489882624.

The previous prime is 768816557. The next prime is 768816571. The reversal of 768816561 is 165618867.

It is not a de Polignac number, because 768816561 - 2² = 768816557 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 768816561.

It is not an unprimeable number, because it can be changed into a prime (768816511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 106705 + ... + 113681.

It is an arithmetic number, because the mean of its divisors is an integer number (66905064).

Almost surely, 2^768816561 is an apocalyptic number.

It is an amenable number.

768816561 is a deficient number, since it is larger than the sum of its proper divisors (301664463).

768816561 is a wasteful number, since it uses less digits than its factorization.

768816561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8600.

The product of its digits is 483840, while the sum is 48.

The square root of 768816561 is about 27727.5415606938. The cubic root of 768816561 is about 916.0958377665.

The spelling of 768816561 in words is "seven hundred sixty-eight million, eight hundred sixteen thousand, five hundred sixty-one".