51321 has 4 divisors (see below), whose sum is σ = 68432. Its totient is φ = 34212.

The previous prime is 51307. The next prime is 51329. The reversal of 51321 is 12315.

51321 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 51321 - 2⁶ = 51257 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 14.

It is a junction number, because it is equal to n+sod(n) for n = 51297 and 51306.

It is not an unprimeable number, because it can be changed into a prime (51329) 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, 8551 + ... + 8556.

It is an arithmetic number, because the mean of its divisors is an integer number (17108).

2⁵¹³²¹ is an apocalyptic number.

It is an amenable number.

51321 is a deficient number, since it is larger than the sum of its proper divisors (17111).

51321 is a wasteful number, since it uses less digits than its factorization.

51321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17110.

The product of its digits is 30, while the sum is 12.

The square root of 51321 is about 226.5413869473. The cubic root of 51321 is about 37.1619393354.

Adding to 51321 its reverse (12315), we get a palindrome (63636).

It can be divided in two parts, 5 and 1321, that added together give a triangular number (1326 = T₅₁).

The spelling of 51321 in words is "fifty-one thousand, three hundred twenty-one".