51939840 has 80 divisors (see below), whose sum is σ = 166069728. Its totient is φ = 13848576.

The previous prime is 51939821. The next prime is 51939857. The reversal of 51939840 is 4893915.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4299 + ... + 11061.

Almost surely, 2^51939840 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 51939840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83034864).

51939840 is an abundant number, since it is smaller than the sum of its proper divisors (114129888).

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

51939840 is an equidigital number, since it uses as much as digits as its factorization.

51939840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6789 (or 6773 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 39.

The square root of 51939840 is about 7206.9299982725. The cubic root of 51939840 is about 373.1071191934.

The spelling of 51939840 in words is "fifty-one million, nine hundred thirty-nine thousand, eight hundred forty".