816643404 has 48 divisors (see below), whose sum is σ = 2125347840. Its totient is φ = 271170000.

The previous prime is 816643397. The next prime is 816643411. The reversal of 816643404 is 404346618.

816643404 is a `hidden beast` number, since 8 + 1 + 6 + 643 + 4 + 0 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (816643397) and next prime (816643411).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14029 + ... + 42779.

It is an arithmetic number, because the mean of its divisors is an integer number (44278080).

Almost surely, 2^816643404 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 816643404, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1062673920).

816643404 is an abundant number, since it is smaller than the sum of its proper divisors (1308704436).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

816643404 is a wasteful number, since it uses less digits than its factorization.

816643404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29027 (or 29019 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The square root of 816643404 is about 28576.9733176906. The cubic root of 816643404 is about 934.7112853137.

The spelling of 816643404 in words is "eight hundred sixteen million, six hundred forty-three thousand, four hundred four".