261421053064261 has 2 divisors, whose sum is σ = 261421053064262. Its totient is φ = 261421053064260.

The previous prime is 261421053064253. The next prime is 261421053064279. The reversal of 261421053064261 is 162460350124162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 218648537459361 + 42772515604900 = 14786769^2 + 6540070^2 .

It is a cyclic number.

It is not a de Polignac number, because 261421053064261 - 2³ = 261421053064253 is a prime.

It is a super-2 number, since 2×261421053064261² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261421053064211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130710526532130 + 130710526532131.

It is an arithmetic number, because the mean of its divisors is an integer number (130710526532131).

Almost surely, 2^{261421053064261} is an apocalyptic number.

It is an amenable number.

261421053064261 is a deficient number, since it is larger than the sum of its proper divisors (1).

261421053064261 is an equidigital number, since it uses as much as digits as its factorization.

261421053064261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 414720, while the sum is 43.

The spelling of 261421053064261 in words is "two hundred sixty-one trillion, four hundred twenty-one billion, fifty-three million, sixty-four thousand, two hundred sixty-one".