51638 has 4 divisors (see below), whose sum is σ = 77460. Its totient is φ = 25818.
The previous prime is 51637. The next prime is 51647. The reversal of 51638 is 83615.
It is a semiprime because it is the product of two primes.
It is a plaindrome in base 8.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (51631) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12908 + ... + 12911.
It is an arithmetic number, because the mean of its divisors is an integer number (19365).
251638 is an apocalyptic number.
51638 is a deficient number, since it is larger than the sum of its proper divisors (25822).
51638 is a wasteful number, since it uses less digits than its factorization.
51638 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 25821.
The product of its digits is 720, while the sum is 23.
The square root of 51638 is about 227.2399612744. The cubic root of 51638 is about 37.2382963998.
Subtracting from 51638 its sum of digits (23), we obtain a palindrome (51615).
The spelling of 51638 in words is "fifty-one thousand, six hundred thirty-eight".
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