816400 has 60 divisors (see below), whose sum is σ = 2125732. Its totient is φ = 299520.

The previous prime is 816377. The next prime is 816401. The reversal of 816400 is 4618.

It can be written as a sum of positive squares in 6 ways, for example, as 150544 + 665856 = 388^2 + 816^2 .

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (816401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5122 + ... + 5278.

2⁸¹⁶⁴⁰⁰ is an apocalyptic number.

816400 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 816400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1062866).

816400 is an abundant number, since it is smaller than the sum of its proper divisors (1309332).

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

816400 is a wasteful number, since it uses less digits than its factorization.

816400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188 (or 177 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 816400 is about 903.5485598461. The cubic root of 816400 is about 93.4618411210.

It can be divided in two parts, 81 and 6400, that multiplied together give a square (518400 = 720²).

The spelling of 816400 in words is "eight hundred sixteen thousand, four hundred".