649643 has 2 divisors, whose sum is σ = 649644. Its totient is φ = 649642.

The previous prime is 649639. The next prime is 649651. The reversal of 649643 is 346946.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 649643 - 2² = 649639 is a prime.

It is not a weakly prime, because it can be changed into another prime (649613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324821 + 324822.

It is an arithmetic number, because the mean of its divisors is an integer number (324822).

2⁶⁴⁹⁶⁴³ is an apocalyptic number.

649643 is a deficient number, since it is larger than the sum of its proper divisors (1).

649643 is an equidigital number, since it uses as much as digits as its factorization.

649643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 32.

The square root of 649643 is about 806.0043424201. The cubic root of 649643 is about 86.6080487908.

The spelling of 649643 in words is "six hundred forty-nine thousand, six hundred forty-three".