51781968 has 120 divisors (see below), whose sum is σ = 169298688. Its totient is φ = 14466816.

The previous prime is 51781943. The next prime is 51781969. The reversal of 51781968 is 86918715.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

Its product of digits (120960) is a multiple of the sum of its prime divisors (1152).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51781969) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 46830 + ... + 47922.

Almost surely, 2^51781968 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 51781968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84649344).

51781968 is an abundant number, since it is smaller than the sum of its proper divisors (117516720).

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

51781968 is a wasteful number, since it uses less digits than its factorization.

51781968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1161 (or 1152 counting only the distinct ones).

The product of its digits is 120960, while the sum is 45.

The square root of 51781968 is about 7195.9688715280. The cubic root of 51781968 is about 372.7287137975.

The spelling of 51781968 in words is "fifty-one million, seven hundred eighty-one thousand, nine hundred sixty-eight".