642711728 has 10 divisors (see below), whose sum is σ = 1245254004. Its totient is φ = 321355856.

The previous prime is 642711709. The next prime is 642711739. The reversal of 642711728 is 827117246.

It is a junction number, because it is equal to n+sod(n) for n = 642711691 and 642711700.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20084726 + ... + 20084757.

Almost surely, 2^642711728 is an apocalyptic number.

It is an amenable number.

642711728 is a deficient number, since it is larger than the sum of its proper divisors (602542276).

642711728 is a wasteful number, since it uses less digits than its factorization.

642711728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40169491 (or 40169485 counting only the distinct ones).

The product of its digits is 37632, while the sum is 38.

The square root of 642711728 is about 25351.7598600176. The cubic root of 642711728 is about 862.9892945344.

The spelling of 642711728 in words is "six hundred forty-two million, seven hundred eleven thousand, seven hundred twenty-eight".