669639 has 16 divisors (see below), whose sum is σ = 950400. Its totient is φ = 418656.

The previous prime is 669637. The next prime is 669649. The reversal of 669639 is 936966.

It is not a de Polignac number, because 669639 - 2¹ = 669637 is a prime.

669639 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 669597 and 669606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669637) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3652 + ... + 3830.

It is an arithmetic number, because the mean of its divisors is an integer number (59400).

2⁶⁶⁹⁶³⁹ is an apocalyptic number.

669639 is a deficient number, since it is larger than the sum of its proper divisors (280761).

669639 is a wasteful number, since it uses less digits than its factorization.

669639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254.

The product of its digits is 52488, while the sum is 39.

The square root of 669639 is about 818.3147316284. The cubic root of 669639 is about 87.4876826199.

The spelling of 669639 in words is "six hundred sixty-nine thousand, six hundred thirty-nine".