669278669 has 2 divisors, whose sum is σ = 669278670. Its totient is φ = 669278668.

The previous prime is 669278651. The next prime is 669278671. The reversal of 669278669 is 966872966.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 504541444 + 164737225 = 22462^2 + 12835^2 .

It is a cyclic number.

It is not a de Polignac number, because 669278669 - 2⁸ = 669278413 is a prime.

It is a super-2 number, since 2×669278669² = 895867873556823122, which contains 22 as substring.

Together with 669278671, 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 (669278609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334639334 + 334639335.

It is an arithmetic number, because the mean of its divisors is an integer number (334639335).

Almost surely, 2^669278669 is an apocalyptic number.

It is an amenable number.

669278669 is a deficient number, since it is larger than the sum of its proper divisors (1).

669278669 is an equidigital number, since it uses as much as digits as its factorization.

669278669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11757312, while the sum is 59.

The square root of 669278669 is about 25870.4207348856. The cubic root of 669278669 is about 874.7198750643.

The spelling of 669278669 in words is "six hundred sixty-nine million, two hundred seventy-eight thousand, six hundred sixty-nine".