261565625309 has 8 divisors (see below), whose sum is σ = 270602428320. Its totient is φ = 252529975600.

The previous prime is 261565625291. The next prime is 261565625329. The reversal of 261565625309 is 903526565162.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261565625309 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 (261565625329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 186374 + ... + 746904.

It is an arithmetic number, because the mean of its divisors is an integer number (33825303540).

Almost surely, 2^261565625309 is an apocalyptic number.

261565625309 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

261565625309 is a deficient number, since it is larger than the sum of its proper divisors (9036803011).

261565625309 is a wasteful number, since it uses less digits than its factorization.

261565625309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 576651.

The product of its (nonzero) digits is 2916000, while the sum is 50.

The spelling of 261565625309 in words is "two hundred sixty-one billion, five hundred sixty-five million, six hundred twenty-five thousand, three hundred nine".