51123800 has 144 divisors (see below), whose sum is σ = 149105040. Its totient is φ = 15874560.

The previous prime is 51123797. The next prime is 51123803. The reversal of 51123800 is 832115.

51123800 = 1418² + 1419² + ... + 1442².

It is an interprime number because it is at equal distance from previous prime (51123797) and next prime (51123803).

It is a super-2 number, since 2×51123800² = 5227285852880000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51123803) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 964574 + ... + 964626.

Almost surely, 2^51123800 is an apocalyptic number.

51123800 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 51123800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (74552520).

51123800 is an abundant number, since it is smaller than the sum of its proper divisors (97981240).

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

51123800 is a wasteful number, since it uses less digits than its factorization.

51123800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142 (or 80 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 51123800 is about 7150.0909085130. The cubic root of 51123800 is about 371.1428021696.

Adding to 51123800 its reverse (832115), we get a palindrome (51955915).

The spelling of 51123800 in words is "fifty-one million, one hundred twenty-three thousand, eight hundred".