649666 has 8 divisors (see below), whose sum is σ = 981180. Its totient is φ = 322608.

The previous prime is 649661. The next prime is 649697. The reversal of 649666 is 666946.

649666 is nontrivially palindromic in base 5.

649666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 594441 + 55225 = 771^2 + 235^2 .

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

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.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 721 + ... + 1348.

2⁶⁴⁹⁶⁶⁶ is an apocalyptic number.

649666 is a deficient number, since it is larger than the sum of its proper divisors (331514).

649666 is a wasteful number, since it uses less digits than its factorization.

649666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2228.

The product of its digits is 46656, while the sum is 37.

The square root of 649666 is about 806.0186102070. The cubic root of 649666 is about 86.6090708709.

It can be divided in two parts, 649 and 666, that multiplied together give a palindrome (432234).

The spelling of 649666 in words is "six hundred forty-nine thousand, six hundred sixty-six".