66398251853 has 2 divisors, whose sum is σ = 66398251854. Its totient is φ = 66398251852.

The previous prime is 66398251831. The next prime is 66398251867. The reversal of 66398251853 is 35815289366.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37986789604 + 28411462249 = 194902^2 + 168557^2 .

It is a cyclic number.

It is not a de Polignac number, because 66398251853 - 2¹² = 66398247757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66398251873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33199125926 + 33199125927.

It is an arithmetic number, because the mean of its divisors is an integer number (33199125927).

Almost surely, 2^66398251853 is an apocalyptic number.

It is an amenable number.

66398251853 is a deficient number, since it is larger than the sum of its proper divisors (1).

66398251853 is an equidigital number, since it uses as much as digits as its factorization.

66398251853 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9331200, while the sum is 56.

The spelling of 66398251853 in words is "sixty-six billion, three hundred ninety-eight million, two hundred fifty-one thousand, eight hundred fifty-three".