669861 has 12 divisors (see below), whose sum is σ = 974688. Its totient is φ = 443304.

The previous prime is 669859. The next prime is 669863. The reversal of 669861 is 168966.

It is an interprime number because it is at equal distance from previous prime (669859) and next prime (669863).

It is not a de Polignac number, because 669861 - 2¹ = 669859 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669863) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2226 + ... + 2508.

It is an arithmetic number, because the mean of its divisors is an integer number (81224).

2⁶⁶⁹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

669861 is a deficient number, since it is larger than the sum of its proper divisors (304827).

669861 is a wasteful number, since it uses less digits than its factorization.

669861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 552 (or 549 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 669861 is about 818.4503650192. The cubic root of 669861 is about 87.4973495796.

The spelling of 669861 in words is "six hundred sixty-nine thousand, eight hundred sixty-one".