51811968 has 128 divisors (see below), whose sum is σ = 151139520. Its totient is φ = 15630336.

The previous prime is 51811967. The next prime is 51811979. The reversal of 51811968 is 86911815.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (51811961) 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, 484171 + ... + 484277.

Almost surely, 2^51811968 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 51811968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (75569760).

51811968 is an abundant number, since it is smaller than the sum of its proper divisors (99327552).

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

51811968 is a wasteful number, since it uses less digits than its factorization.

51811968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234 (or 222 counting only the distinct ones).

The product of its digits is 17280, while the sum is 39.

The square root of 51811968 is about 7198.0530701017. The cubic root of 51811968 is about 372.8006803085.

The spelling of 51811968 in words is "fifty-one million, eight hundred eleven thousand, nine hundred sixty-eight".