261904761905 has 8 divisors (see below), whose sum is σ = 332773109352. Its totient is φ = 197198879488.

The previous prime is 261904761887. The next prime is 261904761977. The reversal of 261904761905 is 509167409162.

It can be written as a sum of positive squares in 4 ways, for example, as 19162311184 + 242742450721 = 138428^2 + 492689^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 261904761905 - 2¹⁶ = 261904696369 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1540616162 + ... + 1540616331.

It is an arithmetic number, because the mean of its divisors is an integer number (41596638669).

Almost surely, 2^261904761905 is an apocalyptic number.

It is an amenable number.

261904761905 is a deficient number, since it is larger than the sum of its proper divisors (70868347447).

261904761905 is a wasteful number, since it uses less digits than its factorization.

261904761905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3081232515.

The product of its (nonzero) digits is 816480, while the sum is 50.

The spelling of 261904761905 in words is "two hundred sixty-one billion, nine hundred four million, seven hundred sixty-one thousand, nine hundred five".