261517430230405 has 8 divisors (see below), whose sum is σ = 313966676120472. Its totient is φ = 209116770955008.

The previous prime is 261517430230393. The next prime is 261517430230409. The reversal of 261517430230405 is 504032034715162.

It can be written as a sum of positive squares in 4 ways, for example, as 16718424459489 + 244799005770916 = 4088817^2 + 15646054^2 .

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 261517430230405 - 2¹⁵ = 261517430197637 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 (261517430230409) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12146641824 + ... + 12146663353.

It is an arithmetic number, because the mean of its divisors is an integer number (39245834515059).

Almost surely, 2^{261517430230405} is an apocalyptic number.

It is an amenable number.

261517430230405 is a deficient number, since it is larger than the sum of its proper divisors (52449245890067).

261517430230405 is a wasteful number, since it uses less digits than its factorization.

261517430230405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24293307335.

The product of its (nonzero) digits is 604800, while the sum is 43.

Adding to 261517430230405 its reverse (504032034715162), we get a palindrome (765549464945567).

The spelling of 261517430230405 in words is "two hundred sixty-one trillion, five hundred seventeen billion, four hundred thirty million, two hundred thirty thousand, four hundred five".