1816861200 has 540 divisors, whose sum is σ = 7527674448. Its totient is φ = 370406400.

The previous prime is 1816861183. The next prime is 1816861201. The reversal of 1816861200 is 21686181.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (1816861201) by changing a digit.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 34280374 + ... + 34280426.

Almost surely, 2^1816861200 is an apocalyptic number.

1816861200 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 1816861200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3763837224).

1816861200 is an abundant number, since it is smaller than the sum of its proper divisors (5710813248).

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

1816861200 is a wasteful number, since it uses less digits than its factorization.

1816861200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 33.

The square root of 1816861200 is about 42624.6548373122. The cubic root of 1816861200 is about 1220.2268681383.

Multiplying 1816861200 by its sum of digits (33), we get a square (59956419600 = 244860²).

1816861200 divided by its sum of digits (33) gives a square (55056400 = 7420²).

The spelling of 1816861200 in words is "one billion, eight hundred sixteen million, eight hundred sixty-one thousand, two hundred".