2505555861 has 4 divisors (see below), whose sum is σ = 3340741152. Its totient is φ = 1670370572.

The previous prime is 2505555851. The next prime is 2505555883. The reversal of 2505555861 is 1685555052.

It is a happy number.

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 2505555861 - 2⁷ = 2505555733 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2505555851) 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, 417592641 + ... + 417592646.

It is an arithmetic number, because the mean of its divisors is an integer number (835185288).

Almost surely, 2^2505555861 is an apocalyptic number.

It is an amenable number.

2505555861 is a deficient number, since it is larger than the sum of its proper divisors (835185291).

2505555861 is an equidigital number, since it uses as much as digits as its factorization.

2505555861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 835185290.

The product of its (nonzero) digits is 300000, while the sum is 42.

The square root of 2505555861 is about 50055.5277766602. The cubic root of 2505555861 is about 1358.2134595691.

It can be divided in two parts, 250 and 5555861, that added together give a triangular number (5556111 = T₃₃₃₃).

The spelling of 2505555861 in words is "two billion, five hundred five million, five hundred fifty-five thousand, eight hundred sixty-one".