669820 has 24 divisors (see below), whose sum is σ = 1424304. Its totient is φ = 264576.

The previous prime is 669791. The next prime is 669839. The reversal of 669820 is 28966.

669820 = T₃₆₁ + T₃₆₂ + ... + T₃₇₀.

669820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

669820 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1984 + ... + 2296.

It is an arithmetic number, because the mean of its divisors is an integer number (59346).

2⁶⁶⁹⁸²⁰ is an apocalyptic number.

It is an amenable number.

669820 is an abundant number, since it is smaller than the sum of its proper divisors (754484).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

669820 is a wasteful number, since it uses less digits than its factorization.

669820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 429 (or 427 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 669820 is about 818.4253173015. The cubic root of 669820 is about 87.4955644010.

The spelling of 669820 in words is "six hundred sixty-nine thousand, eight hundred twenty".