648521 has 4 divisors (see below), whose sum is σ = 655044. Its totient is φ = 642000.

The previous prime is 648509. The next prime is 648563. The reversal of 648521 is 125846.

648521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 436921 + 211600 = 661^2 + 460^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-648521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (641521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3110 + ... + 3311.

It is an arithmetic number, because the mean of its divisors is an integer number (163761).

2⁶⁴⁸⁵²¹ is an apocalyptic number.

It is an amenable number.

648521 is a deficient number, since it is larger than the sum of its proper divisors (6523).

648521 is a wasteful number, since it uses less digits than its factorization.

648521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6522.

The product of its digits is 1920, while the sum is 26.

The square root of 648521 is about 805.3080156065. The cubic root of 648521 is about 86.5581597349.

The spelling of 648521 in words is "six hundred forty-eight thousand, five hundred twenty-one".