664450261 has 2 divisors, whose sum is σ = 664450262. Its totient is φ = 664450260.

The previous prime is 664450217. The next prime is 664450337. The reversal of 664450261 is 162054466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 574560900 + 89889361 = 23970^2 + 9481^2 .

It is a cyclic number.

It is not a de Polignac number, because 664450261 - 2⁹ = 664449749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664450201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332225130 + 332225131.

It is an arithmetic number, because the mean of its divisors is an integer number (332225131).

Almost surely, 2^664450261 is an apocalyptic number.

It is an amenable number.

664450261 is a deficient number, since it is larger than the sum of its proper divisors (1).

664450261 is an equidigital number, since it uses as much as digits as its factorization.

664450261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34560, while the sum is 34.

The square root of 664450261 is about 25776.9327306412. The cubic root of 664450261 is about 872.6112855482.

The spelling of 664450261 in words is "six hundred sixty-four million, four hundred fifty thousand, two hundred sixty-one".