2001023440400 has 120 divisors (see below), whose sum is σ = 5091615928224. Its totient is φ = 753124403200.

The previous prime is 2001023440397. The next prime is 2001023440487. The reversal of 2001023440400 is 40443201002.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26638895 + ... + 26713905.

Almost surely, 2^{2001023440400} is an apocalyptic number.

2001023440400 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 2001023440400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2545807964112).

2001023440400 is an abundant number, since it is smaller than the sum of its proper divisors (3090592487824).

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

2001023440400 is a wasteful number, since it uses less digits than its factorization.

2001023440400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78969 (or 78958 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

Adding to 2001023440400 its reverse (40443201002), we get a palindrome (2041466641402).

The spelling of 2001023440400 in words is "two trillion, one billion, twenty-three million, four hundred forty thousand, four hundred".