261494708549 has 4 divisors (see below), whose sum is σ = 269930021760. Its totient is φ = 253059395340.

The previous prime is 261494708521. The next prime is 261494708551. The reversal of 261494708549 is 945807494162.

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 a de Polignac number, because none of the positive numbers 2^k-261494708549 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 (261494708149) 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, 4217656559 + ... + 4217656620.

It is an arithmetic number, because the mean of its divisors is an integer number (67482505440).

Almost surely, 2^261494708549 is an apocalyptic number.

It is an amenable number.

261494708549 is a deficient number, since it is larger than the sum of its proper divisors (8435313211).

261494708549 is an equidigital number, since it uses as much as digits as its factorization.

261494708549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8435313210.

The product of its (nonzero) digits is 17418240, while the sum is 59.

The spelling of 261494708549 in words is "two hundred sixty-one billion, four hundred ninety-four million, seven hundred eight thousand, five hundred forty-nine".