648138321 has 16 divisors (see below), whose sum is σ = 1001953920. Its totient is φ = 413305200.

The previous prime is 648138301. The next prime is 648138329. The reversal of 648138321 is 123831846.

648138321 is a `hidden beast` number, since 648 + 1 + 3 + 8 + 3 + 2 + 1 = 666.

It is not a de Polignac number, because 648138321 - 2⁷ = 648138193 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (648138329) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 521230 + ... + 522471.

It is an arithmetic number, because the mean of its divisors is an integer number (62622120).

Almost surely, 2^648138321 is an apocalyptic number.

It is an amenable number.

648138321 is a deficient number, since it is larger than the sum of its proper divisors (353815599).

648138321 is a wasteful number, since it uses less digits than its factorization.

648138321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1043733 (or 1043727 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 648138321 is about 25458.5608587760. The cubic root of 648138321 is about 865.4113098418.

The spelling of 648138321 in words is "six hundred forty-eight million, one hundred thirty-eight thousand, three hundred twenty-one".