261620667317 has 4 divisors (see below), whose sum is σ = 261706814796. Its totient is φ = 261534519840.

The previous prime is 261620667277. The next prime is 261620667397. The reversal of 261620667317 is 713766026162.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 190018399921 + 71602267396 = 435911^2 + 267586^2 .

It is a cyclic number.

It is not a de Polignac number, because 261620667317 - 2¹² = 261620663221 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 (261620667397) 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 3 ways as a sum of consecutive naturals, for example, 43069184 + ... + 43075257.

It is an arithmetic number, because the mean of its divisors is an integer number (65426703699).

Almost surely, 2^261620667317 is an apocalyptic number.

It is an amenable number.

261620667317 is a deficient number, since it is larger than the sum of its proper divisors (86147479).

261620667317 is an equidigital number, since it uses as much as digits as its factorization.

261620667317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86147478.

The product of its (nonzero) digits is 762048, while the sum is 47.

The spelling of 261620667317 in words is "two hundred sixty-one billion, six hundred twenty million, six hundred sixty-seven thousand, three hundred seventeen".