819947161 has 4 divisors (see below), whose sum is σ = 894487824. Its totient is φ = 745406500.

The previous prime is 819947143. The next prime is 819947173. The reversal of 819947161 is 161749918.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 819947161 - 2¹⁵ = 819914393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (819942161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37270315 + ... + 37270336.

It is an arithmetic number, because the mean of its divisors is an integer number (223621956).

Almost surely, 2^819947161 is an apocalyptic number.

It is an amenable number.

819947161 is a deficient number, since it is larger than the sum of its proper divisors (74540663).

819947161 is a wasteful number, since it uses less digits than its factorization.

819947161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74540662.

The product of its digits is 108864, while the sum is 46.

The square root of 819947161 is about 28634.7195027295. The cubic root of 819947161 is about 935.9700574985.

The spelling of 819947161 in words is "eight hundred nineteen million, nine hundred forty-seven thousand, one hundred sixty-one".