649864 has 8 divisors (see below), whose sum is σ = 1218510. Its totient is φ = 324928.

The previous prime is 649849. The next prime is 649867. The reversal of 649864 is 468946.

649864 is nontrivially palindromic in base 7.

It can be written as a sum of positive squares in only one way, i.e., 532900 + 116964 = 730^2 + 342^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an Ulam number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649867) by changing a digit.

649864 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 as a sum of consecutive naturals, namely, 40609 + ... + 40624.

2⁶⁴⁹⁸⁶⁴ is an apocalyptic number.

It is an amenable number.

649864 is a deficient number, since it is larger than the sum of its proper divisors (568646).

649864 is a wasteful number, since it uses less digits than its factorization.

649864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81239 (or 81235 counting only the distinct ones).

The product of its digits is 41472, while the sum is 37.

The square root of 649864 is about 806.1414267981. The cubic root of 649864 is about 86.6178686502.

The spelling of 649864 in words is "six hundred forty-nine thousand, eight hundred sixty-four".