669858 has 32 divisors (see below), whose sum is σ = 1572480. Its totient is φ = 186240.

The previous prime is 669857. The next prime is 669859. The reversal of 669858 is 858966.

It is an interprime number because it is at equal distance from previous prime (669857) and next prime (669859).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (669853) 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, 1528 + ... + 1916.

It is an arithmetic number, because the mean of its divisors is an integer number (49140).

2⁶⁶⁹⁸⁵⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 669858, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (786240).

669858 is an abundant number, since it is smaller than the sum of its proper divisors (902622).

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

669858 is a wasteful number, since it uses less digits than its factorization.

669858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 442.

The product of its digits is 103680, while the sum is 42.

The square root of 669858 is about 818.4485322853. The cubic root of 669858 is about 87.4972189592.

The spelling of 669858 in words is "six hundred sixty-nine thousand, eight hundred fifty-eight".