2001081600 has 486 divisors, whose sum is σ = 8334108510. Its totient is φ = 456744960.

The previous prime is 2001081559. The next prime is 2001081617. The reversal of 2001081600 is 61801002.

It can be written as a sum of positive squares in 3 ways, for example, as 4064256 + 1997017344 = 2016^2 + 44688^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 2822046 + ... + 2822754.

Almost surely, 2^2001081600 is an apocalyptic number.

2001081600 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 2001081600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4167054255).

2001081600 is an abundant number, since it is smaller than the sum of its proper divisors (6333026910).

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

2001081600 is a wasteful number, since it uses less digits than its factorization.

2001081600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 755 (or 726 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 2001081600 is about 44733.4505711330. The cubic root of 2001081600 is about 1260.1481307326.

Adding to 2001081600 its reverse (61801002), we get a palindrome (2062882602).

The spelling of 2001081600 in words is "two billion, one million, eighty-one thousand, six hundred".