648638 has 4 divisors (see below), whose sum is σ = 972960. Its totient is φ = 324318.

The previous prime is 648631. The next prime is 648649. The reversal of 648638 is 836846.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 836846 = 2 ⋅418423.

It is a junction number, because it is equal to n+sod(n) for n = 648598 and 648607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (648631) 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 as a sum of consecutive naturals, namely, 162158 + ... + 162161.

It is an arithmetic number, because the mean of its divisors is an integer number (243240).

2⁶⁴⁸⁶³⁸ is an apocalyptic number.

648638 is a deficient number, since it is larger than the sum of its proper divisors (324322).

648638 is a wasteful number, since it uses less digits than its factorization.

648638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324321.

The product of its digits is 27648, while the sum is 35.

The square root of 648638 is about 805.3806553426. The cubic root of 648638 is about 86.5633647557.

The spelling of 648638 in words is "six hundred forty-eight thousand, six hundred thirty-eight".