649820 has 12 divisors (see below), whose sum is σ = 1364664. Its totient is φ = 259920.

The previous prime is 649813. The next prime is 649829. The reversal of 649820 is 28946.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649829) by changing a digit.

649820 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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, 16226 + ... + 16265.

It is an arithmetic number, because the mean of its divisors is an integer number (113722).

2⁶⁴⁹⁸²⁰ is an apocalyptic number.

It is an amenable number.

649820 is an abundant number, since it is smaller than the sum of its proper divisors (714844).

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

649820 is a wasteful number, since it uses less digits than its factorization.

649820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32500 (or 32498 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 649820 is about 806.1141358393. The cubic root of 649820 is about 86.6159137426.

The spelling of 649820 in words is "six hundred forty-nine thousand, eight hundred twenty".