819781949194 has 16 divisors (see below), whose sum is σ = 1325373226632. Its totient is φ = 378043734528.

The previous prime is 819781949179. The next prime is 819781949243. The reversal of 819781949194 is 491949187918.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 770597798569 + 49184150625 = 877837^2 + 221775^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13183599 + ... + 13245634.

Almost surely, 2^819781949194 is an apocalyptic number.

819781949194 is a deficient number, since it is larger than the sum of its proper divisors (505591277438).

819781949194 is a wasteful number, since it uses less digits than its factorization.

819781949194 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26430441.

The product of its digits is 47029248, while the sum is 70.

The spelling of 819781949194 in words is "eight hundred nineteen billion, seven hundred eighty-one million, nine hundred forty-nine thousand, one hundred ninety-four".