649811 has 4 divisors (see below), whose sum is σ = 655992. Its totient is φ = 643632.

The previous prime is 649801. The next prime is 649813. The reversal of 649811 is 118946.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 118946 = 2 ⋅59473.

It is a cyclic number.

It is not a de Polignac number, because 649811 - 2¹⁴ = 633427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (649813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2930 + ... + 3143.

It is an arithmetic number, because the mean of its divisors is an integer number (163998).

2⁶⁴⁹⁸¹¹ is an apocalyptic number.

649811 is a deficient number, since it is larger than the sum of its proper divisors (6181).

649811 is a wasteful number, since it uses less digits than its factorization.

649811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6180.

The product of its digits is 1728, while the sum is 29.

The square root of 649811 is about 806.1085534840. The cubic root of 649811 is about 86.6155138643.

The spelling of 649811 in words is "six hundred forty-nine thousand, eight hundred eleven".