669581 has 8 divisors (see below), whose sum is σ = 756000. Its totient is φ = 587440.

The previous prime is 669577. The next prime is 669607. The reversal of 669581 is 185966.

669581 = T₇₈ + T₇₉ + ... + T₁₆₄.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 669581 - 2² = 669577 is a prime.

It is a super-2 number, since 2×669581² = 896677431122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 669581.

It is not an unprimeable number, because it can be changed into a prime (669551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 731 + ... + 1368.

It is an arithmetic number, because the mean of its divisors is an integer number (94500).

2⁶⁶⁹⁵⁸¹ is an apocalyptic number.

It is an amenable number.

669581 is a deficient number, since it is larger than the sum of its proper divisors (86419).

669581 is a wasteful number, since it uses less digits than its factorization.

669581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2139.

The product of its digits is 12960, while the sum is 35.

The square root of 669581 is about 818.2792921735. The cubic root of 669581 is about 87.4851566658.

It can be divided in two parts, 6695 and 81, that added together give a palindrome (6776).

The spelling of 669581 in words is "six hundred sixty-nine thousand, five hundred eighty-one".