643644627 has 16 divisors (see below), whose sum is σ = 942639360. Its totient is φ = 388837152.

The previous prime is 643644623. The next prime is 643644671. The reversal of 643644627 is 726446346.

It is not a de Polignac number, because 643644627 - 2² = 643644623 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643644623) 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, 244168 + ... + 246789.

It is an arithmetic number, because the mean of its divisors is an integer number (58914960).

Almost surely, 2^643644627 is an apocalyptic number.

643644627 is a deficient number, since it is larger than the sum of its proper divisors (298994733).

643644627 is a wasteful number, since it uses less digits than its factorization.

643644627 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 491002.

The product of its digits is 580608, while the sum is 42.

The square root of 643644627 is about 25370.1522857077. The cubic root of 643644627 is about 863.4066369717.

The spelling of 643644627 in words is "six hundred forty-three million, six hundred forty-four thousand, six hundred twenty-seven".