664020121 has 2 divisors, whose sum is σ = 664020122. Its totient is φ = 664020120.

The previous prime is 664020107. The next prime is 664020127. The reversal of 664020121 is 121020466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 523265625 + 140754496 = 22875^2 + 11864^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664020121 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 664020092 and 664020101.

It is not a weakly prime, because it can be changed into another prime (664020127) 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, 332010060 + 332010061.

It is an arithmetic number, because the mean of its divisors is an integer number (332010061).

Almost surely, 2^664020121 is an apocalyptic number.

It is an amenable number.

664020121 is a deficient number, since it is larger than the sum of its proper divisors (1).

664020121 is an equidigital number, since it uses as much as digits as its factorization.

664020121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 664020121 is about 25768.5878736108. The cubic root of 664020121 is about 872.4229463730.

Adding to 664020121 its reverse (121020466), we get a palindrome (785040587).

The spelling of 664020121 in words is "six hundred sixty-four million, twenty thousand, one hundred twenty-one".