649021 has 4 divisors (see below), whose sum is σ = 683200. Its totient is φ = 614844.

The previous prime is 649007. The next prime is 649039. The reversal of 649021 is 120946.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 649021 - 2⁹ = 648509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 648983 and 649001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17061 + ... + 17098.

It is an arithmetic number, because the mean of its divisors is an integer number (170800).

2⁶⁴⁹⁰²¹ is an apocalyptic number.

It is an amenable number.

649021 is a deficient number, since it is larger than the sum of its proper divisors (34179).

649021 is a wasteful number, since it uses less digits than its factorization.

649021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34178.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 649021 is about 805.6183960164. The cubic root of 649021 is about 86.5803990364.

Adding to 649021 its reverse (120946), we get a palindrome (769967).

The spelling of 649021 in words is "six hundred forty-nine thousand, twenty-one".