2001681123840 has 480 divisors, whose sum is σ = 7501764606336. Its totient is φ = 510570086400.

The previous prime is 2001681123839. The next prime is 2001681123847. The reversal of 2001681123840 is 483211861002.

2001681123840 is a `hidden beast` number, since 2 + 0 + 0 + 168 + 112 + 384 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 2001681123795 and 2001681123804.

It is not an unprimeable number, because it can be changed into a prime (2001681123847) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 14237890 + ... + 14377790.

Almost surely, 2^{2001681123840} is an apocalyptic number.

2001681123840 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 2001681123840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3750882303168).

2001681123840 is an abundant number, since it is smaller than the sum of its proper divisors (5500083482496).

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

2001681123840 is an equidigital number, since it uses as much as digits as its factorization.

2001681123840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139962 (or 139934 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

Adding to 2001681123840 its reverse (483211861002), we get a palindrome (2484892984842).

The spelling of 2001681123840 in words is "two trillion, one billion, six hundred eighty-one million, one hundred twenty-three thousand, eight hundred forty".