669688841 has 2 divisors, whose sum is σ = 669688842. Its totient is φ = 669688840.

The previous prime is 669688813. The next prime is 669688843. The reversal of 669688841 is 148886966.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 652291600 + 17397241 = 25540^2 + 4171^2 .

It is a cyclic number.

It is not a de Polignac number, because 669688841 - 2²² = 665494537 is a prime.

Together with 669688843, 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 (669688843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334844420 + 334844421.

It is an arithmetic number, because the mean of its divisors is an integer number (334844421).

Almost surely, 2^669688841 is an apocalyptic number.

It is an amenable number.

669688841 is a deficient number, since it is larger than the sum of its proper divisors (1).

669688841 is an equidigital number, since it uses as much as digits as its factorization.

669688841 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3981312, while the sum is 56.

The square root of 669688841 is about 25878.3469526166. The cubic root of 669688841 is about 874.8985312541.

The spelling of 669688841 in words is "six hundred sixty-nine million, six hundred eighty-eight thousand, eight hundred forty-one".