2181945600 has 648 divisors, whose sum is σ = 8579992512. Its totient is φ = 547430400.

The previous prime is 2181945599. The next prime is 2181945629. The reversal of 2181945600 is 65491812.

2181945600 is a `hidden beast` number, since 2 + 1 + 8 + 1 + 9 + 45 + 600 = 666.

It is a tau number, because it is divible by the number of its divisors (648).

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 71 ways as a sum of consecutive naturals, for example, 35769570 + ... + 35769630.

Almost surely, 2^2181945600 is an apocalyptic number.

2181945600 is a gapful number since it is divisible by the number (20) 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 2181945600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4289996256).

2181945600 is an abundant number, since it is smaller than the sum of its proper divisors (6398046912).

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

2181945600 is an equidigital number, since it uses as much as digits as its factorization.

2181945600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125 (or 94 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 2181945600 is about 46711.3005599288. The cubic root of 2181945600 is about 1297.0238822447.

The spelling of 2181945600 in words is "two billion, one hundred eighty-one million, nine hundred forty-five thousand, six hundred".