261443337217 has 16 divisors (see below), whose sum is σ = 282672138240. Its totient is φ = 240962853888.

The previous prime is 261443337203. The next prime is 261443337223. The reversal of 261443337217 is 712733344162.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 261443337217 - 2¹¹ = 261443335169 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261443337247) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9974433 + ... + 10000609.

It is an arithmetic number, because the mean of its divisors is an integer number (17667008640).

Almost surely, 2^261443337217 is an apocalyptic number.

It is an amenable number.

261443337217 is a deficient number, since it is larger than the sum of its proper divisors (21228801023).

261443337217 is a wasteful number, since it uses less digits than its factorization.

261443337217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40440.

The product of its digits is 508032, while the sum is 43.

The spelling of 261443337217 in words is "two hundred sixty-one billion, four hundred forty-three million, three hundred thirty-seven thousand, two hundred seventeen".