51121728 has 168 divisors, whose sum is σ = 173288960. Its totient is φ = 14100480.

The previous prime is 51121717. The next prime is 51121729. The reversal of 51121728 is 82712115.

It is a tau number, because it is divible by the number of its divisors (168).

It is a super-2 number, since 2×51121728² = 5226862147411968, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51121729) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 124788 + ... + 125196.

Almost surely, 2^51121728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51121728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86644480).

51121728 is an abundant number, since it is smaller than the sum of its proper divisors (122167232).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51121728 is a wasteful number, since it uses less digits than its factorization.

51121728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 465 (or 452 counting only the distinct ones).

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

The square root of 51121728 is about 7149.9460137822. The cubic root of 51121728 is about 371.1377880778.

The spelling of 51121728 in words is "fifty-one million, one hundred twenty-one thousand, seven hundred twenty-eight".