51490728 has 88 divisors (see below), whose sum is σ = 146145450. Its totient is φ = 17006112.

The previous prime is 51490727. The next prime is 51490781. The reversal of 51490728 is 82709415.

51490728 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 39917124 + 11573604 = 6318^2 + 3402^2 .

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 = 51490692 and 51490701.

It is not an unprimeable number, because it can be changed into a prime (51490723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 21 ways as a sum of consecutive naturals, for example, 472338 + ... + 472446.

Almost surely, 2^51490728 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 51490728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (73072725).

51490728 is an abundant number, since it is smaller than the sum of its proper divisors (94654722).

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

51490728 is an equidigital number, since it uses as much as digits as its factorization.

51490728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145 (or 114 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 51490728 is about 7175.7040072734. The cubic root of 51490728 is about 372.0286138240.

The spelling of 51490728 in words is "fifty-one million, four hundred ninety thousand, seven hundred twenty-eight".