261671597917 has 2 divisors, whose sum is σ = 261671597918. Its totient is φ = 261671597916.

The previous prime is 261671597909. The next prime is 261671597939. The reversal of 261671597917 is 719795176162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 208875506841 + 52796091076 = 457029^2 + 229774^2 .

It is a cyclic number.

It is not a de Polignac number, because 261671597917 - 2³ = 261671597909 is a prime.

It is a super-2 number, since 2×261671597917² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261671591917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130835798958 + 130835798959.

It is an arithmetic number, because the mean of its divisors is an integer number (130835798959).

Almost surely, 2^261671597917 is an apocalyptic number.

It is an amenable number.

261671597917 is a deficient number, since it is larger than the sum of its proper divisors (1).

261671597917 is an equidigital number, since it uses as much as digits as its factorization.

261671597917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10001880, while the sum is 61.

The spelling of 261671597917 in words is "two hundred sixty-one billion, six hundred seventy-one million, five hundred ninety-seven thousand, nine hundred seventeen".