768534508921 has 3 divisors (see below), whose sum is σ = 768535385583. Its totient is φ = 768533632260.

The previous prime is 768534508919. The next prime is 768534508957. The reversal of 768534508921 is 129805435867.

The square root of 768534508921 is 876661.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 129805435867 = 271333 ⋅478399.

It can be written as a sum of positive squares in only one way, i.e., 14450684521 + 754083824400 = 120211^2 + 868380^2 .

It is not a de Polignac number, because 768534508921 - 2¹ = 768534508919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (768534503921) 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 2 ways as a sum of consecutive naturals, for example, 438331 + ... + 1314991.

It is an arithmetic number, because the mean of its divisors is an integer number (256178461861).

It is a 2-persistent number, because it is pandigital, and so is 2⋅768534508921 = 1537069017842, but 3⋅768534508921 = 2305603526763 is not.

Almost surely, 2^768534508921 is an apocalyptic number.

768534508921 is the 876661-st square number.

768534508921 is the 438331-st centered octagonal number.

It is an amenable number.

768534508921 is a deficient number, since it is larger than the sum of its proper divisors (876662).

768534508921 is an frugal number, since it uses more digits than its factorization.

768534508921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1753322 (or 876661 counting only the distinct ones).

The product of its (nonzero) digits is 14515200, while the sum is 58.

The spelling of 768534508921 in words is "seven hundred sixty-eight billion, five hundred thirty-four million, five hundred eight thousand, nine hundred twenty-one".