664156523 has 2 divisors, whose sum is σ = 664156524. Its totient is φ = 664156522.

The previous prime is 664156447. The next prime is 664156531. The reversal of 664156523 is 325651466.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 664156523 - 2¹² = 664152427 is a prime.

It is a super-2 number, since 2×664156523² = 882207774086899058, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (664156553) 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, 332078261 + 332078262.

It is an arithmetic number, because the mean of its divisors is an integer number (332078262).

Almost surely, 2^664156523 is an apocalyptic number.

664156523 is a deficient number, since it is larger than the sum of its proper divisors (1).

664156523 is an equidigital number, since it uses as much as digits as its factorization.

664156523 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129600, while the sum is 38.

The square root of 664156523 is about 25771.2344097057. The cubic root of 664156523 is about 872.4826795466.

The spelling of 664156523 in words is "six hundred sixty-four million, one hundred fifty-six thousand, five hundred twenty-three".