649668 has 12 divisors (see below), whose sum is σ = 1515920. Its totient is φ = 216552.

The previous prime is 649661. The next prime is 649697. The reversal of 649668 is 866946.

649668 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (12).

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (649661) by changing a digit.

649668 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27058 + ... + 27081.

2⁶⁴⁹⁶⁶⁸ is an apocalyptic number.

It is an amenable number.

649668 is an abundant number, since it is smaller than the sum of its proper divisors (866252).

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

649668 is a wasteful number, since it uses less digits than its factorization.

649668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54146 (or 54144 counting only the distinct ones).

The product of its digits is 62208, while the sum is 39.

The square root of 649668 is about 806.0198508722. The cubic root of 649668 is about 86.6091597463.

The spelling of 649668 in words is "six hundred forty-nine thousand, six hundred sixty-eight".