51728121 has 12 divisors (see below), whose sum is σ = 74816560. Its totient is φ = 34440120.

The previous prime is 51728113. The next prime is 51728137. The reversal of 51728121 is 12182715.

51728121 is a `hidden beast` number, since 517 + 28 + 121 = 666.

It is not a de Polignac number, because 51728121 - 2³ = 51728113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (56728121) 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, 4386 + ... + 11076.

Almost surely, 2^51728121 is an apocalyptic number.

It is an amenable number.

51728121 is a deficient number, since it is larger than the sum of its proper divisors (23088439).

51728121 is a wasteful number, since it uses less digits than its factorization.

51728121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7556 (or 7553 counting only the distinct ones).

The product of its digits is 1120, while the sum is 27.

The square root of 51728121 is about 7192.2264285825. The cubic root of 51728121 is about 372.5994713556.

The spelling of 51728121 in words is "fifty-one million, seven hundred twenty-eight thousand, one hundred twenty-one".