42721728 has 168 divisors, whose sum is σ = 138988800. Its totient is φ = 11515392.

The previous prime is 42721711. The next prime is 42721733. The reversal of 42721728 is 82712724.

It is a tau number, because it is divible by the number of its divisors (168).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

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, 178633 + ... + 178871.

Almost surely, 2^42721728 is an apocalyptic number.

42721728 is a gapful number since it is divisible by the number (48) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 42721728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (69494400).

42721728 is an abundant number, since it is smaller than the sum of its proper divisors (96267072).

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

42721728 is a wasteful number, since it uses less digits than its factorization.

42721728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287 (or 270 counting only the distinct ones).

The product of its digits is 12544, while the sum is 33.

The square root of 42721728 is about 6536.1860438638. The cubic root of 42721728 is about 349.5824353594.

It can be divided in two parts, 427 and 21728, that added together give a triangular number (22155 = T₂₁₀).

The spelling of 42721728 in words is "forty-two million, seven hundred twenty-one thousand, seven hundred twenty-eight".