261666374641433 has 2 divisors, whose sum is σ = 261666374641434. Its totient is φ = 261666374641432.

The previous prime is 261666374641391. The next prime is 261666374641499. The reversal of 261666374641433 is 334146473666162.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 259854303280009 + 1812071361424 = 16119997^2 + 1346132^2 .

It is a cyclic number.

It is not a de Polignac number, because 261666374641433 - 2²⁰ = 261666373592857 is a prime.

It is a super-3 number, since 3×261666374641433³ (a number of 44 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (261666374643433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130833187320716 + 130833187320717.

It is an arithmetic number, because the mean of its divisors is an integer number (130833187320717).

Almost surely, 2^{261666374641433} is an apocalyptic number.

It is an amenable number.

261666374641433 is a deficient number, since it is larger than the sum of its proper divisors (1).

261666374641433 is an equidigital number, since it uses as much as digits as its factorization.

261666374641433 is an evil number, because the sum of its binary digits is even.

The product of its digits is 188116992, while the sum is 62.

The spelling of 261666374641433 in words is "two hundred sixty-one trillion, six hundred sixty-six billion, three hundred seventy-four million, six hundred forty-one thousand, four hundred thirty-three".