2001661200 has 960 divisors, whose sum is σ = 9299404800. Its totient is φ = 396748800.

The previous prime is 2001661163. The next prime is 2001661219. The reversal of 2001661200 is 21661002.

It is a happy number.

2001661200 is a `hidden beast` number, since 2 + 0 + 0 + 1 + 661 + 2 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 24116359 + ... + 24116441.

It is an arithmetic number, because the mean of its divisors is an integer number (9686880).

Almost surely, 2^2001661200 is an apocalyptic number.

2001661200 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 2001661200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4649702400).

2001661200 is an abundant number, since it is smaller than the sum of its proper divisors (7297743600).

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

2001661200 is a wasteful number, since it uses less digits than its factorization.

2001661200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157 (or 140 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 2001661200 is about 44739.9284755798. The cubic root of 2001661200 is about 1260.2697835013.

The spelling of 2001661200 in words is "two billion, one million, six hundred sixty-one thousand, two hundred".