66404281 has 2 divisors, whose sum is σ = 66404282. Its totient is φ = 66404280.

The previous prime is 66404267. The next prime is 66404321. The reversal of 66404281 is 18240466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42784681 + 23619600 = 6541^2 + 4860^2 .

It is a cyclic number.

It is not a de Polignac number, because 66404281 - 2¹⁷ = 66273209 is a prime.

It is a super-2 number, since 2×66404281² = 8819057070253922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66404581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33202140 + 33202141.

It is an arithmetic number, because the mean of its divisors is an integer number (33202141).

Almost surely, 2^66404281 is an apocalyptic number.

It is an amenable number.

66404281 is a deficient number, since it is larger than the sum of its proper divisors (1).

66404281 is an equidigital number, since it uses as much as digits as its factorization.

66404281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9216, while the sum is 31.

The square root of 66404281 is about 8148.8821932827. The cubic root of 66404281 is about 404.9474727386.

The spelling of 66404281 in words is "sixty-six million, four hundred four thousand, two hundred eighty-one".