51421 has 2 divisors, whose sum is σ = 51422. Its totient is φ = 51420.

The previous prime is 51419. The next prime is 51427. The reversal of 51421 is 12415.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45796 + 5625 = 214^2 + 75^2 .

It is a cyclic number.

It is not a de Polignac number, because 51421 - 2¹ = 51419 is a prime.

Together with 51419, it forms a pair of twin primes.

51421 is a lucky number.

It is equal to p₅₂₆₀ and since 51421 and 5260 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 51421.

It is not a weakly prime, because it can be changed into another prime (51427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25710 + 25711.

It is an arithmetic number, because the mean of its divisors is an integer number (25711).

2⁵¹⁴²¹ is an apocalyptic number.

It is an amenable number.

51421 is a deficient number, since it is larger than the sum of its proper divisors (1).

51421 is an equidigital number, since it uses as much as digits as its factorization.

51421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40, while the sum is 13.

The square root of 51421 is about 226.7619897602. The cubic root of 51421 is about 37.1860606038.

Adding to 51421 its reverse (12415), we get a palindrome (63836).

It can be divided in two parts, 514 and 21, that added together give a palindrome (535).

The spelling of 51421 in words is "fifty-one thousand, four hundred twenty-one".