51128172 has 72 divisors (see below), whose sum is σ = 139915776. Its totient is φ = 16294608.

The previous prime is 51128171. The next prime is 51128173. The reversal of 51128172 is 27182115.

51128172 is a `hidden beast` number, since 511 + 2 + 81 + 72 = 666.

It is an interprime number because it is at equal distance from previous prime (51128171) and next prime (51128173).

It is a super-3 number, since 3×51128172³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (51128171) 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, 21213 + ... + 23499.

Almost surely, 2^51128172 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 51128172, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (69957888).

51128172 is an abundant number, since it is smaller than the sum of its proper divisors (88787604).

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

51128172 is a wasteful number, since it uses less digits than its factorization.

51128172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2329 (or 2315 counting only the distinct ones).

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

The square root of 51128172 is about 7150.3966323554. The cubic root of 51128172 is about 371.1533816523.

The spelling of 51128172 in words is "fifty-one million, one hundred twenty-eight thousand, one hundred seventy-two".