649621 has 16 divisors (see below), whose sum is σ = 808704. Its totient is φ = 509184.

The previous prime is 649619. The next prime is 649631. The reversal of 649621 is 126946.

It is not a de Polignac number, because 649621 - 2¹ = 649619 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 649621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649631) 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 15 ways as a sum of consecutive naturals, for example, 6256 + ... + 6358.

It is an arithmetic number, because the mean of its divisors is an integer number (50544).

2⁶⁴⁹⁶²¹ is an apocalyptic number.

It is an amenable number.

649621 is a deficient number, since it is larger than the sum of its proper divisors (159083).

649621 is a wasteful number, since it uses less digits than its factorization.

649621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180.

The product of its digits is 2592, while the sum is 28.

The square root of 649621 is about 805.9906947354. The cubic root of 649621 is about 86.6070711264.

The spelling of 649621 in words is "six hundred forty-nine thousand, six hundred twenty-one".