51728643 has 12 divisors (see below), whose sum is σ = 74781720. Its totient is φ = 34456896.

The previous prime is 51728639. The next prime is 51728731. The reversal of 51728643 is 34682715.

51728643 is a `hidden beast` number, since 5 + 1 + 7 + 2 + 8 + 643 = 666.

It is not a de Polignac number, because 51728643 - 2² = 51728639 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 51728598 and 51728607.

It is not an unprimeable number, because it can be changed into a prime (51728843) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18523 + ... + 21131.

It is an arithmetic number, because the mean of its divisors is an integer number (6231810).

Almost surely, 2^51728643 is an apocalyptic number.

51728643 is a deficient number, since it is larger than the sum of its proper divisors (23053077).

51728643 is a wasteful number, since it uses less digits than its factorization.

51728643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4818 (or 4815 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 51728643 is about 7192.2627176710. The cubic root of 51728643 is about 372.6007246795.

The spelling of 51728643 in words is "fifty-one million, seven hundred twenty-eight thousand, six hundred forty-three".