2001857561 has 8 divisors (see below), whose sum is σ = 2234632224. Its totient is φ = 1777547520.

The previous prime is 2001857527. The next prime is 2001857569. The reversal of 2001857561 is 1657581002.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2001857561 - 2⁶ = 2001857497 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2001857569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2115656 + ... + 2116601.

It is an arithmetic number, because the mean of its divisors is an integer number (279329028).

Almost surely, 2^2001857561 is an apocalyptic number.

It is an amenable number.

2001857561 is a deficient number, since it is larger than the sum of its proper divisors (232774663).

2001857561 is a wasteful number, since it uses less digits than its factorization.

2001857561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4232311.

The product of its (nonzero) digits is 16800, while the sum is 35.

The square root of 2001857561 is about 44742.1228933094. The cubic root of 2001857561 is about 1260.3109925636.

The spelling of 2001857561 in words is "two billion, one million, eight hundred fifty-seven thousand, five hundred sixty-one".