666669 has 8 divisors (see below), whose sum is σ = 903712. Its totient is φ = 437040.

The previous prime is 666667. The next prime is 666671. The reversal of 666669 is 966666.

It is an interprime number because it is at equal distance from previous prime (666667) and next prime (666671).

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

It is not a de Polignac number, because 666669 - 2¹ = 666667 is a prime.

It is a super-2 number, since 2×666669² = 888895111122, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 10.

It is a nialpdrome in base 7.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1639 + ... + 2004.

It is an arithmetic number, because the mean of its divisors is an integer number (112964).

2⁶⁶⁶⁶⁶⁹ is an apocalyptic number.

It is an amenable number.

666669 is a deficient number, since it is larger than the sum of its proper divisors (237043).

666669 is a wasteful number, since it uses less digits than its factorization.

666669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3707.

The product of its digits is 69984, while the sum is 39.

The square root of 666669 is about 816.4980097955. The cubic root of 666669 is about 87.3581483912.

It can be divided in two parts, 6666 and 69, that multiplied together give a palindrome (459954).

The spelling of 666669 in words is "six hundred sixty-six thousand, six hundred sixty-nine".