261441642109 has 4 divisors (see below), whose sum is σ = 261449951616. Its totient is φ = 261433332604.

The previous prime is 261441642103. The next prime is 261441642139. The reversal of 261441642109 is 901246144162.

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 261441642109 - 2¹³ = 261441633917 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261441642103) 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, 4107379 + ... + 4170544.

It is an arithmetic number, because the mean of its divisors is an integer number (65362487904).

Almost surely, 2^261441642109 is an apocalyptic number.

It is an amenable number.

261441642109 is a deficient number, since it is larger than the sum of its proper divisors (8309507).

261441642109 is an equidigital number, since it uses as much as digits as its factorization.

261441642109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8309506.

The product of its (nonzero) digits is 82944, while the sum is 40.

The spelling of 261441642109 in words is "two hundred sixty-one billion, four hundred forty-one million, six hundred forty-two thousand, one hundred nine".