66665513 has 2 divisors, whose sum is σ = 66665514. Its totient is φ = 66665512.

The previous prime is 66665479. The next prime is 66665537. The reversal of 66665513 is 31556666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 59413264 + 7252249 = 7708^2 + 2693^2 .

It is a cyclic number.

It is not a de Polignac number, because 66665513 - 2¹² = 66661417 is a prime.

It is not a weakly prime, because it can be changed into another prime (66665213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33332756 + 33332757.

It is an arithmetic number, because the mean of its divisors is an integer number (33332757).

Almost surely, 2^66665513 is an apocalyptic number.

It is an amenable number.

66665513 is a deficient number, since it is larger than the sum of its proper divisors (1).

66665513 is an equidigital number, since it uses as much as digits as its factorization.

66665513 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 97200, while the sum is 38.

The square root of 66665513 is about 8164.8951616050. The cubic root of 66665513 is about 405.4777940802.

The spelling of 66665513 in words is "sixty-six million, six hundred sixty-five thousand, five hundred thirteen".