61312533209 has 2 divisors, whose sum is σ = 61312533210. Its totient is φ = 61312533208.

The previous prime is 61312533133. The next prime is 61312533211. The reversal of 61312533209 is 90233521316.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42930596809 + 18381936400 = 207197^2 + 135580^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61312533209 is a prime.

It is a Sophie Germain prime.

Together with 61312533211, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (61312533229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30656266604 + 30656266605.

It is an arithmetic number, because the mean of its divisors is an integer number (30656266605).

Almost surely, 2^61312533209 is an apocalyptic number.

It is an amenable number.

61312533209 is a deficient number, since it is larger than the sum of its proper divisors (1).

61312533209 is an equidigital number, since it uses as much as digits as its factorization.

61312533209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 29160, while the sum is 35.

The spelling of 61312533209 in words is "sixty-one billion, three hundred twelve million, five hundred thirty-three thousand, two hundred nine".