51881 has 4 divisors (see below), whose sum is σ = 53700. Its totient is φ = 50064.

The previous prime is 51871. The next prime is 51893. The reversal of 51881 is 18815.

51881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 40000 + 11881 = 200^2 + 109^2 .

It is a cyclic number.

It is not a de Polignac number, because 51881 - 2⁶ = 51817 is a prime.

It is a super-2 number, since 2×51881² = 5383276322, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51871) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 866 + ... + 923.

It is an arithmetic number, because the mean of its divisors is an integer number (13425).

2⁵¹⁸⁸¹ is an apocalyptic number.

It is an amenable number.

51881 is a deficient number, since it is larger than the sum of its proper divisors (1819).

51881 is a wasteful number, since it uses less digits than its factorization.

51881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1818.

The product of its digits is 320, while the sum is 23.

The square root of 51881 is about 227.7740108090. The cubic root of 51881 is about 37.2966174605.

The spelling of 51881 in words is "fifty-one thousand, eight hundred eighty-one".