816638019 has 8 divisors (see below), whose sum is σ = 1112017920. Its totient is φ = 532841736.

The previous prime is 816637981. The next prime is 816638021. The reversal of 816638019 is 910836618.

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

It is a de Polignac number, because none of the positive numbers 2^k-816638019 is a prime.

It is a super-2 number, since 2×816638019² = 1333795308152488722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (816638029) 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, 2895739 + ... + 2896020.

It is an arithmetic number, because the mean of its divisors is an integer number (139002240).

Almost surely, 2^816638019 is an apocalyptic number.

816638019 is a deficient number, since it is larger than the sum of its proper divisors (295379901).

816638019 is a wasteful number, since it uses less digits than its factorization.

816638019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5791809.

The product of its (nonzero) digits is 62208, while the sum is 42.

The square root of 816638019 is about 28576.8790983200. The cubic root of 816638019 is about 934.7092307934.

The spelling of 816638019 in words is "eight hundred sixteen million, six hundred thirty-eight thousand, nineteen".