51855816 has 64 divisors (see below), whose sum is σ = 134064000. Its totient is φ = 16704000.

The previous prime is 51855809. The next prime is 51855821. The reversal of 51855816 is 61855815.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 148410 + ... + 148758.

It is an arithmetic number, because the mean of its divisors is an integer number (2094750).

Almost surely, 2^51855816 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 51855816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67032000).

51855816 is an abundant number, since it is smaller than the sum of its proper divisors (82208184).

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

51855816 is a wasteful number, since it uses less digits than its factorization.

51855816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 550 (or 546 counting only the distinct ones).

The product of its digits is 48000, while the sum is 39.

The square root of 51855816 is about 7201.0982495728. The cubic root of 51855816 is about 372.9058166036.

Subtracting 51855816 from its reverse (61855815), we obtain a palindrome (9999999).

It can be divided in two parts, 518558 and 16, that multiplied together give a palindrome (8296928).

The spelling of 51855816 in words is "fifty-one million, eight hundred fifty-five thousand, eight hundred sixteen".