669655 has 24 divisors (see below), whose sum is σ = 987552. Its totient is φ = 426816.

The previous prime is 669649. The next prime is 669659. The reversal of 669655 is 556966.

It is a happy number.

It is not a de Polignac number, because 669655 - 2⁷ = 669527 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12609 + ... + 12661.

It is an arithmetic number, because the mean of its divisors is an integer number (41148).

2⁶⁶⁹⁶⁵⁵ is an apocalyptic number.

669655 is a deficient number, since it is larger than the sum of its proper divisors (317897).

669655 is a wasteful number, since it uses less digits than its factorization.

669655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103 (or 84 counting only the distinct ones).

The product of its digits is 48600, while the sum is 37.

The square root of 669655 is about 818.3245077596. The cubic root of 669655 is about 87.4883794092.

Subtracting from 669655 its product of digits (48600), we obtain a triangular number (621055 = T₁₁₁₄).

The spelling of 669655 in words is "six hundred sixty-nine thousand, six hundred fifty-five".