668505121 has 2 divisors, whose sum is σ = 668505122. Its totient is φ = 668505120.

The previous prime is 668505113. The next prime is 668505151. The reversal of 668505121 is 121505866.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 445421025 + 223084096 = 21105^2 + 14936^2 .

It is a cyclic number.

It is not a de Polignac number, because 668505121 - 2³ = 668505113 is a prime.

It is not a weakly prime, because it can be changed into another prime (668505151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334252560 + 334252561.

It is an arithmetic number, because the mean of its divisors is an integer number (334252561).

Almost surely, 2^668505121 is an apocalyptic number.

It is an amenable number.

668505121 is a deficient number, since it is larger than the sum of its proper divisors (1).

668505121 is an equidigital number, since it uses as much as digits as its factorization.

668505121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14400, while the sum is 34.

The square root of 668505121 is about 25855.4659791697. The cubic root of 668505121 is about 874.3827466038.

The spelling of 668505121 in words is "six hundred sixty-eight million, five hundred five thousand, one hundred twenty-one".