66681020249 has 2 divisors, whose sum is σ = 66681020250. Its totient is φ = 66681020248.

The previous prime is 66681020183. The next prime is 66681020257. The reversal of 66681020249 is 94202018666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 59764603024 + 6916417225 = 244468^2 + 83165^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66681020249 is a prime.

It is a super-2 number, since 2×66681020249² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66681020279) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33340510124 + 33340510125.

It is an arithmetic number, because the mean of its divisors is an integer number (33340510125).

Almost surely, 2^66681020249 is an apocalyptic number.

It is an amenable number.

66681020249 is a deficient number, since it is larger than the sum of its proper divisors (1).

66681020249 is an equidigital number, since it uses as much as digits as its factorization.

66681020249 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 248832, while the sum is 44.

The spelling of 66681020249 in words is "sixty-six billion, six hundred eighty-one million, twenty thousand, two hundred forty-nine".