664271081 has 2 divisors, whose sum is σ = 664271082. Its totient is φ = 664271080.

The previous prime is 664271059. The next prime is 664271099. The reversal of 664271081 is 180172466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 660027481 + 4243600 = 25691^2 + 2060^2 .

It is a cyclic number.

It is not a de Polignac number, because 664271081 - 2⁶ = 664271017 is a prime.

It is a super-2 number, since 2×664271081² = 882512138105817122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (664271011) 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, 332135540 + 332135541.

It is an arithmetic number, because the mean of its divisors is an integer number (332135541).

Almost surely, 2^664271081 is an apocalyptic number.

It is an amenable number.

664271081 is a deficient number, since it is larger than the sum of its proper divisors (1).

664271081 is an equidigital number, since it uses as much as digits as its factorization.

664271081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 664271081 is about 25773.4569082225. The cubic root of 664271081 is about 872.5328404756.

The spelling of 664271081 in words is "six hundred sixty-four million, two hundred seventy-one thousand, eighty-one".