661161179321 has 2 divisors, whose sum is σ = 661161179322. Its totient is φ = 661161179320.

The previous prime is 661161179317. The next prime is 661161179323. The reversal of 661161179321 is 123971161166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 418298497600 + 242862681721 = 646760^2 + 492811^2 .

It is a cyclic number.

It is not a de Polignac number, because 661161179321 - 2² = 661161179317 is a prime.

It is a super-2 number, since 2×661161179321² (a number of 24 digits) contains 22 as substring.

Together with 661161179323, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (661161179323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330580589660 + 330580589661.

It is an arithmetic number, because the mean of its divisors is an integer number (330580589661).

Almost surely, 2^661161179321 is an apocalyptic number.

It is an amenable number.

661161179321 is a deficient number, since it is larger than the sum of its proper divisors (1).

661161179321 is an equidigital number, since it uses as much as digits as its factorization.

661161179321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 44.

The spelling of 661161179321 in words is "six hundred sixty-one billion, one hundred sixty-one million, one hundred seventy-nine thousand, three hundred twenty-one".