819642891 has 8 divisors (see below), whose sum is σ = 1100192400. Its totient is φ = 542760992.

The previous prime is 819642871. The next prime is 819642893. The reversal of 819642891 is 198246918.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 819642891 - 2⁷ = 819642763 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 819642891.

It is not an unprimeable number, because it can be changed into a prime (819642893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 916380 + ... + 917273.

It is an arithmetic number, because the mean of its divisors is an integer number (137524050).

Almost surely, 2^819642891 is an apocalyptic number.

819642891 is a deficient number, since it is larger than the sum of its proper divisors (280549509).

819642891 is a wasteful number, since it uses less digits than its factorization.

819642891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1833805.

The product of its digits is 248832, while the sum is 48.

The square root of 819642891 is about 28629.4060539160. The cubic root of 819642891 is about 935.8542683936.

The spelling of 819642891 in words is "eight hundred nineteen million, six hundred forty-two thousand, eight hundred ninety-one".