51516220 has 96 divisors (see below), whose sum is σ = 132088320. Its totient is φ = 16485120.

The previous prime is 51516187. The next prime is 51516221. The reversal of 51516220 is 2261515.

It is a junction number, because it is equal to n+sod(n) for n = 51516191 and 51516200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51516221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 284530 + ... + 284710.

It is an arithmetic number, because the mean of its divisors is an integer number (1375920).

Almost surely, 2^51516220 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51516220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (66044160).

51516220 is an abundant number, since it is smaller than the sum of its proper divisors (80572100).

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

51516220 is a wasteful number, since it uses less digits than its factorization.

51516220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323 (or 321 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 22.

The square root of 51516220 is about 7177.4800591851. The cubic root of 51516220 is about 372.0899982657.

Adding to 51516220 its reverse (2261515), we get a palindrome (53777735).

The spelling of 51516220 in words is "fifty-one million, five hundred sixteen thousand, two hundred twenty".