51318820 has 48 divisors (see below), whose sum is σ = 124467840. Its totient is φ = 17409024.

The previous prime is 51318811. The next prime is 51318821. The reversal of 51318820 is 2881315.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (51318821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11691 + ... + 15469.

It is an arithmetic number, because the mean of its divisors is an integer number (2593080).

Almost surely, 2^51318820 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 51318820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (62233920).

51318820 is an abundant number, since it is smaller than the sum of its proper divisors (73149020).

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

51318820 is a wasteful number, since it uses less digits than its factorization.

51318820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3892 (or 3890 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 51318820 is about 7163.7155164063. The cubic root of 51318820 is about 371.6141314293.

The spelling of 51318820 in words is "fifty-one million, three hundred eighteen thousand, eight hundred twenty".