819671989394 has 16 divisors (see below), whose sum is σ = 1236701601432. Its totient is φ = 407438454528.

The previous prime is 819671989391. The next prime is 819671989447. The reversal of 819671989394 is 493989176918.

It can be written as a sum of positive squares in 4 ways, for example, as 755656411225 + 64015578169 = 869285^2 + 253013^2 .

It is not an unprimeable number, because it can be changed into a prime (819671989391) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5382362 + ... + 5532554.

Almost surely, 2^819671989394 is an apocalyptic number.

819671989394 is a deficient number, since it is larger than the sum of its proper divisors (417029612038).

819671989394 is a wasteful number, since it uses less digits than its factorization.

819671989394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166141.

The product of its digits is 211631616, while the sum is 74.

The spelling of 819671989394 in words is "eight hundred nineteen billion, six hundred seventy-one million, nine hundred eighty-nine thousand, three hundred ninety-four".