664665161 has 2 divisors, whose sum is σ = 664665162. Its totient is φ = 664665160.

The previous prime is 664665139. The next prime is 664665179. The reversal of 664665161 is 161566466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 456036025 + 208629136 = 21355^2 + 14444^2 .

It is a cyclic number.

It is not a de Polignac number, because 664665161 - 2⁶ = 664665097 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (664665121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332332580 + 332332581.

It is an arithmetic number, because the mean of its divisors is an integer number (332332581).

Almost surely, 2^664665161 is an apocalyptic number.

It is an amenable number.

664665161 is a deficient number, since it is larger than the sum of its proper divisors (1).

664665161 is an equidigital number, since it uses as much as digits as its factorization.

664665161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 155520, while the sum is 41.

The square root of 664665161 is about 25781.1008492655. The cubic root of 664665161 is about 872.7053502526.

The spelling of 664665161 in words is "six hundred sixty-four million, six hundred sixty-five thousand, one hundred sixty-one".