2561241618 has 24 divisors (see below), whose sum is σ = 5976230988. Its totient is φ = 788074272.

The previous prime is 2561241581. The next prime is 2561241619. The reversal of 2561241618 is 8161421652.

It is a happy number.

2561241618 is a `hidden beast` number, since 25 + 6 + 12 + 4 + 1 + 618 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 2411497449 + 149744169 = 49107^2 + 12237^2 .

It is not an unprimeable number, because it can be changed into a prime (2561241619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5472505 + ... + 5472972.

Almost surely, 2^2561241618 is an apocalyptic number.

2561241618 is an abundant number, since it is smaller than the sum of its proper divisors (3414989370).

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

2561241618 is a wasteful number, since it uses less digits than its factorization.

2561241618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10945498 (or 10945495 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 2561241618 is about 50608.7108905177. The cubic root of 2561241618 is about 1368.2018816916.

The spelling of 2561241618 in words is "two billion, five hundred sixty-one million, two hundred forty-one thousand, six hundred eighteen".