51138 has 16 divisors (see below), whose sum is σ = 113760. Its totient is φ = 17028.

The previous prime is 51137. The next prime is 51151. The reversal of 51138 is 83115.

It is a happy number.

51138 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a self number, because there is not a number n which added to its sum of digits gives 51138.

It is not an unprimeable number, because it can be changed into a prime (51131) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 420 + ... + 527.

It is an arithmetic number, because the mean of its divisors is an integer number (7110).

2⁵¹¹³⁸ is an apocalyptic number.

51138 is an abundant number, since it is smaller than the sum of its proper divisors (62622).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (56880).

51138 is a wasteful number, since it uses less digits than its factorization.

51138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 958 (or 952 counting only the distinct ones).

The product of its digits is 120, while the sum is 18.

The square root of 51138 is about 226.1371265405. The cubic root of 51138 is about 37.1177161509.

It can be divided in two parts, 5113 and 8, that multiplied together give a palindrome (40904).

The spelling of 51138 in words is "fifty-one thousand, one hundred thirty-eight".