816805440 has 672 divisors, whose sum is σ = 3423513600. Its totient is φ = 176394240.

The previous prime is 816805439. The next prime is 816805441. The reversal of 816805440 is 44508618.

It is an interprime number because it is at equal distance from previous prime (816805439) and next prime (816805441).

It is a super-2 number, since 2×816805440² = 1334342253627187200, which contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 816805395 and 816805404.

It is not an unprimeable number, because it can be changed into a prime (816805441) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 13844131 + ... + 13844189.

Almost surely, 2^816805440 is an apocalyptic number.

816805440 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 816805440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1711756800).

816805440 is an abundant number, since it is smaller than the sum of its proper divisors (2606708160).

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

816805440 is a wasteful number, since it uses less digits than its factorization.

816805440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135 (or 122 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 36.

The square root of 816805440 is about 28579.8082568795. The cubic root of 816805440 is about 934.7731021201.

The spelling of 816805440 in words is "eight hundred sixteen million, eight hundred five thousand, four hundred forty".