668149 has 4 divisors (see below), whose sum is σ = 673164. Its totient is φ = 663136.

The previous prime is 668141. The next prime is 668153. The reversal of 668149 is 941866.

668149 = T₂₂ + T₂₃ + ... + T₁₅₈.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 941866 = 2 ⋅470933.

It can be written as a sum of positive squares in 2 ways, for example, as 286225 + 381924 = 535^2 + 618^2 .

It is a cyclic number.

It is not a de Polignac number, because 668149 - 2³ = 668141 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668141) 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 3 ways as a sum of consecutive naturals, for example, 2302 + ... + 2575.

It is an arithmetic number, because the mean of its divisors is an integer number (168291).

2⁶⁶⁸¹⁴⁹ is an apocalyptic number.

It is an amenable number.

668149 is a deficient number, since it is larger than the sum of its proper divisors (5015).

668149 is a wasteful number, since it uses less digits than its factorization.

668149 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5014.

The product of its digits is 10368, while the sum is 34.

The square root of 668149 is about 817.4038169718. The cubic root of 668149 is about 87.4227454167.

The spelling of 668149 in words is "six hundred sixty-eight thousand, one hundred forty-nine".