2001578120 has 32 divisors (see below), whose sum is σ = 4505765400. Its totient is φ = 800237568.

The previous prime is 2001578107. The next prime is 2001578141. The reversal of 2001578120 is 218751002.

It is a Cunningham number, because it is equal to 44739²-1.

It can be written as a sum of positive squares in 4 ways, for example, as 1796572996 + 205005124 = 42386^2 + 14318^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 2001578120.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78296 + ... + 100664.

Almost surely, 2^2001578120 is an apocalyptic number.

2001578120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2001578120 is an abundant number, since it is smaller than the sum of its proper divisors (2504187280).

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

2001578120 is a wasteful number, since it uses less digits than its factorization.

2001578120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24617 (or 24613 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 2001578120 is about 44738.9999888241. Note that the first 4 decimals coincide. The cubic root of 2001578120 is about 1260.2523472069.

The spelling of 2001578120 in words is "two billion, one million, five hundred seventy-eight thousand, one hundred twenty".