664801606949 has 2 divisors, whose sum is σ = 664801606950. Its totient is φ = 664801606948.

The previous prime is 664801606919. The next prime is 664801606951. The reversal of 664801606949 is 949606108466.

664801606949 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 339023214049 + 325778392900 = 582257^2 + 570770^2 .

It is a cyclic number.

It is not a de Polignac number, because 664801606949 - 2¹² = 664801602853 is a prime.

It is a super-2 number, since 2×664801606949² (a number of 24 digits) contains 22 as substring.

Together with 664801606951, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664801606919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332400803474 + 332400803475.

It is an arithmetic number, because the mean of its divisors is an integer number (332400803475).

Almost surely, 2^664801606949 is an apocalyptic number.

It is an amenable number.

664801606949 is a deficient number, since it is larger than the sum of its proper divisors (1).

664801606949 is an equidigital number, since it uses as much as digits as its factorization.

664801606949 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13436928, while the sum is 59.

The spelling of 664801606949 in words is "six hundred sixty-four billion, eight hundred one million, six hundred six thousand, nine hundred forty-nine".