648639 has 12 divisors (see below), whose sum is σ = 947856. Its totient is φ = 427392.

The previous prime is 648631. The next prime is 648649. The reversal of 648639 is 936846.

648639 is a `hidden beast` number, since 648 + 6 + 3 + 9 = 666.

It is not a de Polignac number, because 648639 - 2³ = 648631 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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 polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 502 + ... + 1244.

It is an arithmetic number, because the mean of its divisors is an integer number (78988).

2⁶⁴⁸⁶³⁹ is an apocalyptic number.

648639 is a deficient number, since it is larger than the sum of its proper divisors (299217).

648639 is a wasteful number, since it uses less digits than its factorization.

648639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 846 (or 843 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 648639 is about 805.3812761668. The cubic root of 648639 is about 86.5634092403.

The spelling of 648639 in words is "six hundred forty-eight thousand, six hundred thirty-nine".