51205 has 24 divisors (see below), whose sum is σ = 82080. Its totient is φ = 30240.

The previous prime is 51203. The next prime is 51217. The reversal of 51205 is 50215.

51205 = 67² + 68² + ... + 76².

It is not a de Polignac number, because 51205 - 2¹ = 51203 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2686 + ... + 2704.

It is an arithmetic number, because the mean of its divisors is an integer number (3420).

2⁵¹²⁰⁵ is an apocalyptic number.

51205 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

It is an amenable number.

51205 is a deficient number, since it is larger than the sum of its proper divisors (30875).

51205 is a wasteful number, since it uses less digits than its factorization.

51205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49 (or 42 counting only the distinct ones).

The product of its (nonzero) digits is 50, while the sum is 13.

The square root of 51205 is about 226.2852182534. The cubic root of 51205 is about 37.1339193766.

Subtracting from 51205 its reverse (50215), we obtain a triangular number (990 = T₄₄).

It can be divided in two parts, 5120 and 5, that multiplied together give a square (25600 = 160²).

The spelling of 51205 in words is "fifty-one thousand, two hundred five".