649640 has 32 divisors (see below), whose sum is σ = 1485000. Its totient is φ = 255744.

The previous prime is 649639. The next prime is 649643. The reversal of 649640 is 46946.

649640 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 4 ways, for example, as 454276 + 195364 = 674^2 + 442^2 .

It is a super-4 number, since 4×649640⁴ (a number of 24 digits) contains 4444 as substring.

It is not an unprimeable number, because it can be changed into a prime (649643) 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, 4286 + ... + 4434.

2⁶⁴⁹⁶⁴⁰ is an apocalyptic number.

It is an amenable number.

649640 is an abundant number, since it is smaller than the sum of its proper divisors (835360).

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

649640 is a wasteful number, since it uses less digits than its factorization.

649640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269 (or 265 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 649640 is about 806.0024813858. The cubic root of 649640 is about 86.6079154742.

The spelling of 649640 in words is "six hundred forty-nine thousand, six hundred forty".