2001121440 has 192 divisors, whose sum is σ = 6739552512. Its totient is φ = 497868800.

The previous prime is 2001121433. The next prime is 2001121457. The reversal of 2001121440 is 441211002.

It is a Harshad number since it is a multiple of its sum of digits (15).

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, 450430 + ... + 454850.

It is an arithmetic number, because the mean of its divisors is an integer number (35101836).

Almost surely, 2^2001121440 is an apocalyptic number.

2001121440 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 2001121440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3369776256).

2001121440 is an abundant number, since it is smaller than the sum of its proper divisors (4738431072).

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

2001121440 is a wasteful number, since it uses less digits than its factorization.

2001121440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4503 (or 4495 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 2001121440 is about 44733.8958732637. The cubic root of 2001121440 is about 1260.1564935381.

Adding to 2001121440 its reverse (441211002), we get a palindrome (2442332442).

The spelling of 2001121440 in words is "two billion, one million, one hundred twenty-one thousand, four hundred forty".