2001121000 has 128 divisors (see below), whose sum is σ = 5053894560. Its totient is φ = 738816000.

The previous prime is 2001120973. The next prime is 2001121019. The reversal of 2001121000 is 1211002.

It can be written as a sum of positive squares in 16 ways, for example, as 39162564 + 1961958436 = 6258^2 + 44294^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 899890 + ... + 902110.

Almost surely, 2^2001121000 is an apocalyptic number.

2001121000 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 2001121000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2526947280).

2001121000 is an abundant number, since it is smaller than the sum of its proper divisors (3052773560).

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

2001121000 is a wasteful number, since it uses less digits than its factorization.

2001121000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2312 (or 2298 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 2001121000 is about 44733.8909552925. The cubic root of 2001121000 is about 1260.1564011784.

Adding to 2001121000 its reverse (1211002), we get a palindrome (2002332002).

The spelling of 2001121000 in words is "two billion, one million, one hundred twenty-one thousand".