669637109 has 2 divisors, whose sum is σ = 669637110. Its totient is φ = 669637108.

The previous prime is 669637099. The next prime is 669637181. The reversal of 669637109 is 901736966.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 652802500 + 16834609 = 25550^2 + 4103^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-669637109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (669637909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334818554 + 334818555.

It is an arithmetic number, because the mean of its divisors is an integer number (334818555).

Almost surely, 2^669637109 is an apocalyptic number.

It is an amenable number.

669637109 is a deficient number, since it is larger than the sum of its proper divisors (1).

669637109 is an equidigital number, since it uses as much as digits as its factorization.

669637109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 367416, while the sum is 47.

The square root of 669637109 is about 25877.3474104283. The cubic root of 669637109 is about 874.8760026739.

The spelling of 669637109 in words is "six hundred sixty-nine million, six hundred thirty-seven thousand, one hundred nine".