51987 has 16 divisors (see below), whose sum is σ = 78848. Its totient is φ = 30240.

The previous prime is 51977. The next prime is 51991. The reversal of 51987 is 78915.

51987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 51987 - 2⁴ = 51971 is a prime.

It is a Duffinian number.

Its product of digits (2520) is a multiple of the sum of its prime divisors (90).

It is not an unprimeable number, because it can be changed into a prime (51907) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1188 + ... + 1230.

It is an arithmetic number, because the mean of its divisors is an integer number (4928).

2⁵¹⁹⁸⁷ is an apocalyptic number.

51987 is a deficient number, since it is larger than the sum of its proper divisors (26861).

51987 is a wasteful number, since it uses less digits than its factorization.

51987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90.

The product of its digits is 2520, while the sum is 30.

The square root of 51987 is about 228.0065788525. The cubic root of 51987 is about 37.3220008830.

It can be divided in two parts, 519 and 87, that added together give a palindrome (606).

The spelling of 51987 in words is "fifty-one thousand, nine hundred eighty-seven".