819693821 has 8 divisors (see below), whose sum is σ = 842429280. Its totient is φ = 797125392.

The previous prime is 819693817. The next prime is 819693829. The reversal of 819693821 is 128396918.

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 819693821 - 2² = 819693817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (819693829) 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 7 ways as a sum of consecutive naturals, for example, 31775 + ... + 51468.

It is an arithmetic number, because the mean of its divisors is an integer number (105303660).

Almost surely, 2^819693821 is an apocalyptic number.

It is an amenable number.

819693821 is a deficient number, since it is larger than the sum of its proper divisors (22735459).

819693821 is a wasteful number, since it uses less digits than its factorization.

819693821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83515.

The product of its digits is 186624, while the sum is 47.

The square root of 819693821 is about 28630.2955101759. The cubic root of 819693821 is about 935.8736516605.

The spelling of 819693821 in words is "eight hundred nineteen million, six hundred ninety-three thousand, eight hundred twenty-one".