819081643 has 4 divisors (see below), whose sum is σ = 836508960. Its totient is φ = 801654328.

The previous prime is 819081623. The next prime is 819081661. The reversal of 819081643 is 346180918.

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

It is a cyclic number.

It is not a de Polignac number, because 819081643 - 2⁵ = 819081611 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 819081596 and 819081605.

It is not an unprimeable number, because it can be changed into a prime (819081623) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8713588 + ... + 8713681.

It is an arithmetic number, because the mean of its divisors is an integer number (209127240).

Almost surely, 2^819081643 is an apocalyptic number.

819081643 is a deficient number, since it is larger than the sum of its proper divisors (17427317).

819081643 is a wasteful number, since it uses less digits than its factorization.

819081643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17427316.

The product of its (nonzero) digits is 41472, while the sum is 40.

The square root of 819081643 is about 28619.6024256103. The cubic root of 819081643 is about 935.6406118224.

The spelling of 819081643 in words is "eight hundred nineteen million, eighty-one thousand, six hundred forty-three".