664348969 has 2 divisors, whose sum is σ = 664348970. Its totient is φ = 664348968.

The previous prime is 664348961. The next prime is 664348973. The reversal of 664348969 is 969843466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 538796944 + 125552025 = 23212^2 + 11205^2 .

It is a cyclic number.

It is not a de Polignac number, because 664348969 - 2³ = 664348961 is a prime.

It is a super-2 number, since 2×664348969² = 882719105222725922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (664348961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332174484 + 332174485.

It is an arithmetic number, because the mean of its divisors is an integer number (332174485).

Almost surely, 2^664348969 is an apocalyptic number.

It is an amenable number.

664348969 is a deficient number, since it is larger than the sum of its proper divisors (1).

664348969 is an equidigital number, since it uses as much as digits as its factorization.

664348969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6718464, while the sum is 55.

The square root of 664348969 is about 25774.9678758287. The cubic root of 664348969 is about 872.5669416048.

The spelling of 664348969 in words is "six hundred sixty-four million, three hundred forty-eight thousand, nine hundred sixty-nine".