768145320721 has 9 divisors (see below), whose sum is σ = 771135900283. Its totient is φ = 765166304560.

The previous prime is 768145320659. The next prime is 768145320779. The reversal of 768145320721 is 127023541867.

The square root of 768145320721 is 876439.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 519104399121 + 249040921600 = 720489^2 + 499040^2 .

It is not a de Polignac number, because 768145320721 - 2²³ = 768136932113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (768145320781) 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 8 ways as a sum of consecutive naturals, for example, 246277800 + ... + 246280918.

Almost surely, 2^768145320721 is an apocalyptic number.

768145320721 is the 876439-th square number.

768145320721 is the 438220-th centered octagonal number.

It is an amenable number.

768145320721 is a deficient number, since it is larger than the sum of its proper divisors (2990579562).

768145320721 is an frugal number, since it uses more digits than its factorization.

768145320721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6800 (or 3400 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 46.

The spelling of 768145320721 in words is "seven hundred sixty-eight billion, one hundred forty-five million, three hundred twenty thousand, seven hundred twenty-one".