51409 has 4 divisors (see below), whose sum is σ = 52020. Its totient is φ = 50800.

The previous prime is 51407. The next prime is 51413. The reversal of 51409 is 90415.

51409 is nontrivially palindromic in base 14.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 46225 + 5184 = 215^2 + 72^2 .

It is a cyclic number.

It is not a de Polignac number, because 51409 - 2¹ = 51407 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 154 + ... + 355.

It is an arithmetic number, because the mean of its divisors is an integer number (13005).

2⁵¹⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

51409 is a deficient number, since it is larger than the sum of its proper divisors (611).

51409 is a wasteful number, since it uses less digits than its factorization.

51409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 51409 is about 226.7355287554. The cubic root of 51409 is about 37.1831677038.

The spelling of 51409 in words is "fifty-one thousand, four hundred nine".