51891216 has 80 divisors (see below), whose sum is σ = 145657344. Its totient is φ = 15823872.

The previous prime is 51891181. The next prime is 51891221. The reversal of 51891216 is 61219815.

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

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, 85185 + ... + 85791.

Almost surely, 2^51891216 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 51891216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72828672).

51891216 is an abundant number, since it is smaller than the sum of its proper divisors (93766128).

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

51891216 is a wasteful number, since it uses less digits than its factorization.

51891216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 768 (or 762 counting only the distinct ones).

The product of its digits is 4320, while the sum is 33.

The square root of 51891216 is about 7203.5557886366. Note that the first 3 decimals coincide. The cubic root of 51891216 is about 372.9906535236.

The spelling of 51891216 in words is "fifty-one million, eight hundred ninety-one thousand, two hundred sixteen".