1816664400 has 180 divisors, whose sum is σ = 6522095580. Its totient is φ = 467712000.

The previous prime is 1816664393. The next prime is 1816664401. The reversal of 1816664400 is 44666181.

It can be written as a sum of positive squares in 6 ways, for example, as 13133376 + 1803531024 = 3624^2 + 42468^2 .

It is a tau number, because it is divible by the number of its divisors (180).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1816664401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 95700 + ... + 113100.

Almost surely, 2^1816664400 is an apocalyptic number.

1816664400 is a gapful number since it is divisible by the number (10) 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 1816664400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3261047790).

1816664400 is an abundant number, since it is smaller than the sum of its proper divisors (4705431180).

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

1816664400 is a wasteful number, since it uses less digits than its factorization.

1816664400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17454 (or 17440 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 1816664400 is about 42622.3462517023. The cubic root of 1816664400 is about 1220.1828087611.

The spelling of 1816664400 in words is "one billion, eight hundred sixteen million, six hundred sixty-four thousand, four hundred".