819642878 has 4 divisors (see below), whose sum is σ = 1229464320. Its totient is φ = 409821438.

The previous prime is 819642871. The next prime is 819642893. The reversal of 819642878 is 878246918.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×819642878² = 1343628894912245768, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (819642871) 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 as a sum of consecutive naturals, namely, 204910718 + ... + 204910721.

It is an arithmetic number, because the mean of its divisors is an integer number (307366080).

Almost surely, 2^819642878 is an apocalyptic number.

819642878 is a deficient number, since it is larger than the sum of its proper divisors (409821442).

819642878 is a wasteful number, since it uses less digits than its factorization.

819642878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409821441.

The product of its digits is 1548288, while the sum is 53.

The square root of 819642878 is about 28629.4058268767. The cubic root of 819642878 is about 935.8542634459.

The spelling of 819642878 in words is "eight hundred nineteen million, six hundred forty-two thousand, eight hundred seventy-eight".