66661038397 has 2 divisors, whose sum is σ = 66661038398. Its totient is φ = 66661038396.

The previous prime is 66661038371. The next prime is 66661038421. The reversal of 66661038397 is 79383016666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46900832356 + 19760206041 = 216566^2 + 140571^2 .

It is a cyclic number.

It is not a de Polignac number, because 66661038397 - 2¹¹ = 66661036349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66661038307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33330519198 + 33330519199.

It is an arithmetic number, because the mean of its divisors is an integer number (33330519199).

Almost surely, 2^66661038397 is an apocalyptic number.

It is an amenable number.

66661038397 is a deficient number, since it is larger than the sum of its proper divisors (1).

66661038397 is an equidigital number, since it uses as much as digits as its factorization.

66661038397 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5878656, while the sum is 55.

The spelling of 66661038397 in words is "sixty-six billion, six hundred sixty-one million, thirty-eight thousand, three hundred ninety-seven".