261612618 has 8 divisors (see below), whose sum is σ = 523225248. Its totient is φ = 87204204.

The previous prime is 261612613. The next prime is 261612619. The reversal of 261612618 is 816216162.

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

261612618 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (261612613) 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, 21801046 + ... + 21801057.

It is an arithmetic number, because the mean of its divisors is an integer number (65403156).

Almost surely, 2^261612618 is an apocalyptic number.

261612618 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

261612618 is a wasteful number, since it uses less digits than its factorization.

261612618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43602108.

The product of its digits is 6912, while the sum is 33.

The square root of 261612618 is about 16174.4433598192. The cubic root of 261612618 is about 639.5672676979.

The spelling of 261612618 in words is "two hundred sixty-one million, six hundred twelve thousand, six hundred eighteen".