2003855561 has 4 divisors (see below), whose sum is σ = 2004226512. Its totient is φ = 2003484612.

The previous prime is 2003855537. The next prime is 2003855563. The reversal of 2003855561 is 1655583002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2003855561 - 2¹⁰ = 2003854537 is a prime.

It is a super-3 number, since 3×2003855561³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2003855563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 177251 + ... + 188216.

It is an arithmetic number, because the mean of its divisors is an integer number (501056628).

Almost surely, 2^2003855561 is an apocalyptic number.

It is an amenable number.

2003855561 is a deficient number, since it is larger than the sum of its proper divisors (370951).

2003855561 is an equidigital number, since it uses as much as digits as its factorization.

2003855561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 370950.

The product of its (nonzero) digits is 36000, while the sum is 35.

The square root of 2003855561 is about 44764.4452774744. The cubic root of 2003855561 is about 1260.7301472738.

The spelling of 2003855561 in words is "two billion, three million, eight hundred fifty-five thousand, five hundred sixty-one".