261661471467013 has 2 divisors, whose sum is σ = 261661471467014. Its totient is φ = 261661471467012.

The previous prime is 261661471466963. The next prime is 261661471467029. The reversal of 261661471467013 is 310764174166162.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 250222316385889 + 11439155081124 = 15818417^2 + 3382182^2 .

It is a cyclic number.

It is not a de Polignac number, because 261661471467013 - 2⁹ = 261661471466501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261661471467313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130830735733506 + 130830735733507.

It is an arithmetic number, because the mean of its divisors is an integer number (130830735733507).

Almost surely, 2^{261661471467013} is an apocalyptic number.

It is an amenable number.

261661471467013 is a deficient number, since it is larger than the sum of its proper divisors (1).

261661471467013 is an equidigital number, since it uses as much as digits as its factorization.

261661471467013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6096384, while the sum is 55.

The spelling of 261661471467013 in words is "two hundred sixty-one trillion, six hundred sixty-one billion, four hundred seventy-one million, four hundred sixty-seven thousand, thirteen".