648421 has 4 divisors (see below), whose sum is σ = 653292. Its totient is φ = 643552.

The previous prime is 648391. The next prime is 648433. The reversal of 648421 is 124846.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 124846 = 2 ⋅62423.

It can be written as a sum of positive squares in 2 ways, for example, as 240100 + 408321 = 490^2 + 639^2 .

It is a cyclic number.

It is not a de Polignac number, because 648421 - 2⁷ = 648293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (648481) 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 3 ways as a sum of consecutive naturals, for example, 2230 + ... + 2503.

It is an arithmetic number, because the mean of its divisors is an integer number (163323).

2⁶⁴⁸⁴²¹ is an apocalyptic number.

It is an amenable number.

648421 is a deficient number, since it is larger than the sum of its proper divisors (4871).

648421 is a wasteful number, since it uses less digits than its factorization.

648421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4870.

The product of its digits is 1536, while the sum is 25.

The square root of 648421 is about 805.2459251682. The cubic root of 648421 is about 86.5537105031.

The spelling of 648421 in words is "six hundred forty-eight thousand, four hundred twenty-one".