51425 has 18 divisors (see below), whose sum is σ = 74214. Its totient is φ = 35200.

The previous prime is 51421. The next prime is 51427. The reversal of 51425 is 52415.

51425 = T₁₈ + T₁₉ + ... + T₆₇.

It can be written as a sum of positive squares in 3 ways, for example, as 7744 + 43681 = 88^2 + 209^2 .

It is not a de Polignac number, because 51425 - 2² = 51421 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 51425.

It is not an unprimeable number, because it can be changed into a prime (51421) 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 17 ways as a sum of consecutive naturals, for example, 3017 + ... + 3033.

It is an arithmetic number, because the mean of its divisors is an integer number (4123).

2⁵¹⁴²⁵ is an apocalyptic number.

51425 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

It is an amenable number.

51425 is a deficient number, since it is larger than the sum of its proper divisors (22789).

51425 is a wasteful number, since it uses less digits than its factorization.

51425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49 (or 33 counting only the distinct ones).

The product of its digits is 200, while the sum is 17.

The square root of 51425 is about 226.7708094090. The cubic root of 51425 is about 37.1870248039.

Multiplying 51425 by its sum of digits (17), we get a square (874225 = 935²).

51425 divided by its sum of digits (17) gives a square (3025 = 55²).

Subtracting 51425 from its reverse (52415), we obtain a triangular number (990 = T₄₄).

The spelling of 51425 in words is "fifty-one thousand, four hundred twenty-five".