66720149 has 2 divisors, whose sum is σ = 66720150. Its totient is φ = 66720148.

The previous prime is 66720109. The next prime is 66720151. The reversal of 66720149 is 94102766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 45468049 + 21252100 = 6743^2 + 4610^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66720149 is a prime.

Together with 66720151, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66720109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33360074 + 33360075.

It is an arithmetic number, because the mean of its divisors is an integer number (33360075).

Almost surely, 2^66720149 is an apocalyptic number.

It is an amenable number.

66720149 is a deficient number, since it is larger than the sum of its proper divisors (1).

66720149 is an equidigital number, since it uses as much as digits as its factorization.

66720149 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 66720149 is about 8168.2402633615. The cubic root of 66720149 is about 405.5885341738.

The spelling of 66720149 in words is "sixty-six million, seven hundred twenty thousand, one hundred forty-nine".