649205 has 4 divisors (see below), whose sum is σ = 779052. Its totient is φ = 519360.

The previous prime is 649183. The next prime is 649217. The reversal of 649205 is 502946.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 502946 = 2 ⋅251473.

It can be written as a sum of positive squares in 2 ways, for example, as 343396 + 305809 = 586^2 + 553^2 .

It is not a de Polignac number, because 649205 - 2⁶ = 649141 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a zygodrome in base 15.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 649205.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64916 + ... + 64925.

It is an arithmetic number, because the mean of its divisors is an integer number (194763).

2⁶⁴⁹²⁰⁵ is an apocalyptic number.

It is an amenable number.

649205 is a deficient number, since it is larger than the sum of its proper divisors (129847).

649205 is a wasteful number, since it uses less digits than its factorization.

649205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129846.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 649205 is about 805.7325859117. The cubic root of 649205 is about 86.5885802243.

The spelling of 649205 in words is "six hundred forty-nine thousand, two hundred five".