51115500 has 144 divisors (see below), whose sum is σ = 166149984. Its totient is φ = 13219200.

The previous prime is 51115483. The next prime is 51115511. The reversal of 51115500 is 551115.

51115500 is a `hidden beast` number, since 5 + 111 + 550 + 0 = 666.

It is a super-2 number, since 2×51115500² = 5225588680500000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 166347 + ... + 166653.

Almost surely, 2^51115500 is an apocalyptic number.

51115500 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 51115500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83074992).

51115500 is an abundant number, since it is smaller than the sum of its proper divisors (115034484).

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

51115500 is a wasteful number, since it uses less digits than its factorization.

51115500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 369 (or 354 counting only the distinct ones).

The product of its (nonzero) digits is 125, while the sum is 18.

The square root of 51115500 is about 7149.5104727527. The cubic root of 51115500 is about 371.1227159477.

Adding to 51115500 its reverse (551115), we get a palindrome (51666615).

It can be divided in two parts, 51115 and 500, that added together give a palindrome (51615).

The spelling of 51115500 in words is "fifty-one million, one hundred fifteen thousand, five hundred".