51680440 has 64 divisors (see below), whose sum is σ = 133516800. Its totient is φ = 17635968.

The previous prime is 51680429. The next prime is 51680443. The reversal of 51680440 is 4408615.

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

It is a junction number, because it is equal to n+sod(n) for n = 51680399 and 51680408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51680443) by changing a digit.

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, 105877 + ... + 106363.

It is an arithmetic number, because the mean of its divisors is an integer number (2086200).

Almost surely, 2^51680440 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 51680440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (66758400).

51680440 is an abundant number, since it is smaller than the sum of its proper divisors (81836360).

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

51680440 is a wasteful number, since it uses less digits than its factorization.

51680440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 884 (or 880 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 51680440 is about 7188.9109049981. The cubic root of 51680440 is about 372.4849535234.

The spelling of 51680440 in words is "fifty-one million, six hundred eighty thousand, four hundred forty".