819723778522 has 12 divisors (see below), whose sum is σ = 1351528048458. Its totient is φ = 372601717400.

The previous prime is 819723778499. The next prime is 819723778543. The reversal of 819723778522 is 225877327918.

It can be written as a sum of positive squares in only one way, i.e., 803495311641 + 16228466881 = 896379^2 + 127391^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1693643929 + ... + 1693644412.

Almost surely, 2^819723778522 is an apocalyptic number.

819723778522 is a deficient number, since it is larger than the sum of its proper divisors (531804269936).

819723778522 is a wasteful number, since it uses less digits than its factorization.

819723778522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3387288365 (or 3387288354 counting only the distinct ones).

The product of its digits is 23708160, while the sum is 61.

The spelling of 819723778522 in words is "eight hundred nineteen billion, seven hundred twenty-three million, seven hundred seventy-eight thousand, five hundred twenty-two".