66721475519 has 2 divisors, whose sum is σ = 66721475520. Its totient is φ = 66721475518.

The previous prime is 66721475459. The next prime is 66721475531. The reversal of 66721475519 is 91557412766.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66721475519 - 2²⁰ = 66720426943 is a prime.

It is a super-2 number, since 2×66721475519² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66721475539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33360737759 + 33360737760.

It is an arithmetic number, because the mean of its divisors is an integer number (33360737760).

Almost surely, 2^66721475519 is an apocalyptic number.

66721475519 is a deficient number, since it is larger than the sum of its proper divisors (1).

66721475519 is an equidigital number, since it uses as much as digits as its factorization.

66721475519 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3175200, while the sum is 53.

The spelling of 66721475519 in words is "sixty-six billion, seven hundred twenty-one million, four hundred seventy-five thousand, five hundred nineteen".