51399 has 6 divisors (see below), whose sum is σ = 74256. Its totient is φ = 34260.

The previous prime is 51383. The next prime is 51407. The reversal of 51399 is 99315.

51399 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 51399 - 2⁴ = 51383 is a prime.

51399 is a lucky number.

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 51399.

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 5 ways as a sum of consecutive naturals, for example, 2847 + ... + 2864.

It is an arithmetic number, because the mean of its divisors is an integer number (12376).

2⁵¹³⁹⁹ is an apocalyptic number.

51399 is a deficient number, since it is larger than the sum of its proper divisors (22857).

51399 is a wasteful number, since it uses less digits than its factorization.

51399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5717 (or 5714 counting only the distinct ones).

The product of its digits is 1215, while the sum is 27.

The square root of 51399 is about 226.7134755589. The cubic root of 51399 is about 37.1807566098.

The spelling of 51399 in words is "fifty-one thousand, three hundred ninety-nine".