66397556573 has 2 divisors, whose sum is σ = 66397556574. Its totient is φ = 66397556572.

The previous prime is 66397556483. The next prime is 66397556657. The reversal of 66397556573 is 37565579366.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65804049529 + 593507044 = 256523^2 + 24362^2 .

It is a cyclic number.

It is not a de Polignac number, because 66397556573 - 2⁸ = 66397556317 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66397556873) 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, 33198778286 + 33198778287.

It is an arithmetic number, because the mean of its divisors is an integer number (33198778287).

Almost surely, 2^66397556573 is an apocalyptic number.

It is an amenable number.

66397556573 is a deficient number, since it is larger than the sum of its proper divisors (1).

66397556573 is an equidigital number, since it uses as much as digits as its factorization.

66397556573 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 107163000, while the sum is 62.

The spelling of 66397556573 in words is "sixty-six billion, three hundred ninety-seven million, five hundred fifty-six thousand, five hundred seventy-three".