51400 has 24 divisors (see below), whose sum is σ = 119970. Its totient is φ = 20480.

The previous prime is 51383. The next prime is 51407. The reversal of 51400 is 415.

It can be written as a sum of positive squares in 3 ways, for example, as 49284 + 2116 = 222^2 + 46^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

51400 is an undulating number in base 16.

It is a plaindrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51407) 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, 72 + ... + 328.

2⁵¹⁴⁰⁰ is an apocalyptic number.

51400 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (59985).

51400 is an abundant number, since it is smaller than the sum of its proper divisors (68570).

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

51400 is a wasteful number, since it uses less digits than its factorization.

51400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273 (or 264 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 10.

The square root of 51400 is about 226.7156809751. The cubic root of 51400 is about 37.1809977333.

Adding to 51400 its reverse (415), we get a palindrome (51815).

The spelling of 51400 in words is "fifty-one thousand, four hundred".