648746021 has 32 divisors (see below), whose sum is σ = 840278016. Its totient is φ = 486072000.

The previous prime is 648746017. The next prime is 648746039. The reversal of 648746021 is 120647846.

It is a cyclic number.

It is not a de Polignac number, because 648746021 - 2² = 648746017 is a prime.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (648746071) 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 in 31 ways as a sum of consecutive naturals, for example, 412166 + ... + 413736.

It is an arithmetic number, because the mean of its divisors is an integer number (26258688).

Almost surely, 2^648746021 is an apocalyptic number.

It is an amenable number.

648746021 is a deficient number, since it is larger than the sum of its proper divisors (191531995).

648746021 is a wasteful number, since it uses less digits than its factorization.

648746021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1793.

The product of its (nonzero) digits is 64512, while the sum is 38.

The square root of 648746021 is about 25470.4931440284. The cubic root of 648746021 is about 865.6816976873.

The spelling of 648746021 in words is "six hundred forty-eight million, seven hundred forty-six thousand, twenty-one".