51819840 has 168 divisors, whose sum is σ = 187817760. Its totient is φ = 13077504.

The previous prime is 51819811. The next prime is 51819841. The reversal of 51819840 is 4891815.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 51819795 and 51819804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51819841) 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 23 ways as a sum of consecutive naturals, for example, 54247 + ... + 55193.

Almost surely, 2^51819840 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 51819840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93908880).

51819840 is an abundant number, since it is smaller than the sum of its proper divisors (135997920).

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

51819840 is a wasteful number, since it uses less digits than its factorization.

51819840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 989 (or 976 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 51819840 is about 7198.5998638624. The cubic root of 51819840 is about 372.8195597196.

The spelling of 51819840 in words is "fifty-one million, eight hundred nineteen thousand, eight hundred forty".