645606555928 has 32 divisors (see below), whose sum is σ = 1254344940000. Its totient is φ = 311151742720.

The previous prime is 645606555917. The next prime is 645606555929. The reversal of 645606555928 is 829555606546.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645606555929) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2183893 + ... + 2461828.

It is an arithmetic number, because the mean of its divisors is an integer number (39198279375).

Almost surely, 2^645606555928 is an apocalyptic number.

It is an amenable number.

645606555928 is a deficient number, since it is larger than the sum of its proper divisors (608738384072).

645606555928 is a wasteful number, since it uses less digits than its factorization.

645606555928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4646355 (or 4646351 counting only the distinct ones).

The product of its (nonzero) digits is 77760000, while the sum is 61.

The spelling of 645606555928 in words is "six hundred forty-five billion, six hundred six million, five hundred fifty-five thousand, nine hundred twenty-eight".