643248656451 has 16 divisors (see below), whose sum is σ = 978716676000. Its totient is φ = 417242371104.

The previous prime is 643248656423. The next prime is 643248656527. The reversal of 643248656451 is 154656842346.

643248656451 is a `hidden beast` number, since 6 + 4 + 3 + 24 + 8 + 6 + 564 + 51 = 666.

It is not a de Polignac number, because 643248656451 - 2⁵ = 643248656419 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643248656951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 321945276 + ... + 321947273.

It is an arithmetic number, because the mean of its divisors is an integer number (61169792250).

Almost surely, 2^643248656451 is an apocalyptic number.

643248656451 is a deficient number, since it is larger than the sum of its proper divisors (335468019549).

643248656451 is a wasteful number, since it uses less digits than its factorization.

643248656451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 643892595 (or 643892589 counting only the distinct ones).

The product of its digits is 16588800, while the sum is 54.

The spelling of 643248656451 in words is "six hundred forty-three billion, two hundred forty-eight million, six hundred fifty-six thousand, four hundred fifty-one".