51906 has 16 divisors (see below), whose sum is σ = 106848. Its totient is φ = 16800.

The previous prime is 51899. The next prime is 51907. The reversal of 51906 is 60915.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51907) by changing a digit.

51906 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 7 ways as a sum of consecutive naturals, for example, 141 + ... + 351.

It is an arithmetic number, because the mean of its divisors is an integer number (6678).

2⁵¹⁹⁰⁶ is an apocalyptic number.

51906 is an abundant number, since it is smaller than the sum of its proper divisors (54942).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53424).

51906 is a wasteful number, since it uses less digits than its factorization.

51906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257.

The product of its (nonzero) digits is 270, while the sum is 21.

The square root of 51906 is about 227.8288831558. The cubic root of 51906 is about 37.3026072301.

Multiplying 51906 by its sum of digits (21), we get a triangular number (1090026 = T₁₄₇₆).

Subtracting 51906 from its reverse (60915), we obtain a palindrome (9009).

The spelling of 51906 in words is "fifty-one thousand, nine hundred six".