261266503405 has 8 divisors (see below), whose sum is σ = 313707663000. Its totient is φ = 208887963456.

The previous prime is 261266503369. The next prime is 261266503411. The reversal of 261266503405 is 504305662162.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 673610116 + 260592893289 = 25954^2 + 510483^2 .

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 261266503405 - 2¹³ = 261266495213 is a prime.

It is a congruent number.

It is an unprimeable number.

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, 15645730 + ... + 15662419.

It is an arithmetic number, because the mean of its divisors is an integer number (39213457875).

Almost surely, 2^261266503405 is an apocalyptic number.

It is an amenable number.

261266503405 is a deficient number, since it is larger than the sum of its proper divisors (52441159595).

261266503405 is a wasteful number, since it uses less digits than its factorization.

261266503405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31309823.

The product of its (nonzero) digits is 259200, while the sum is 40.

The spelling of 261266503405 in words is "two hundred sixty-one billion, two hundred sixty-six million, five hundred three thousand, four hundred five".