648391 has 2 divisors, whose sum is σ = 648392. Its totient is φ = 648390.

The previous prime is 648383. The next prime is 648433. The reversal of 648391 is 193846.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 648391 - 2³ = 648383 is a prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (648331) 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 as a sum of consecutive naturals, namely, 324195 + 324196.

It is an arithmetic number, because the mean of its divisors is an integer number (324196).

2⁶⁴⁸³⁹¹ is an apocalyptic number.

648391 is a deficient number, since it is larger than the sum of its proper divisors (1).

648391 is an equidigital number, since it uses as much as digits as its factorization.

648391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 31.

The square root of 648391 is about 805.2272971031. The cubic root of 648391 is about 86.5523756443.

The spelling of 648391 in words is "six hundred forty-eight thousand, three hundred ninety-one".