665623001 has 2 divisors, whose sum is σ = 665623002. Its totient is φ = 665623000.

The previous prime is 665622959. The next prime is 665623003. The reversal of 665623001 is 100326566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 372528601 + 293094400 = 19301^2 + 17120^2 .

It is a cyclic number.

It is not a de Polignac number, because 665623001 - 2¹⁰ = 665621977 is a prime.

Together with 665623003, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (665623003) 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, 332811500 + 332811501.

It is an arithmetic number, because the mean of its divisors is an integer number (332811501).

Almost surely, 2^665623001 is an apocalyptic number.

It is an amenable number.

665623001 is a deficient number, since it is larger than the sum of its proper divisors (1).

665623001 is an equidigital number, since it uses as much as digits as its factorization.

665623001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 665623001 is about 25799.6705599122. The cubic root of 665623001 is about 873.1243636759.

Adding to 665623001 its reverse (100326566), we get a palindrome (765949567).

The spelling of 665623001 in words is "six hundred sixty-five million, six hundred twenty-three thousand, one".