7129728 has 64 divisors (see below), whose sum is σ = 21052800. Its totient is φ = 2375424.

The previous prime is 7129711. The next prime is 7129729. The reversal of 7129728 is 8279217.

It is a tau number, because it is divible by the number of its divisors (64).

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 = 7129692 and 7129701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7129729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2425 + ... + 4487.

It is an arithmetic number, because the mean of its divisors is an integer number (328950).

Almost surely, 2^7129728 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 7129728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10526400).

7129728 is an abundant number, since it is smaller than the sum of its proper divisors (13923072).

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

7129728 is a wasteful number, since it uses less digits than its factorization.

7129728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2086 (or 2068 counting only the distinct ones).

The product of its digits is 14112, while the sum is 36.

The square root of 7129728 is about 2670.1550516777. The cubic root of 7129728 is about 192.4676102248.

It can be divided in two parts, 712 and 9728, that added together give a triangular number (10440 = T₁₄₄).

The spelling of 7129728 in words is "seven million, one hundred twenty-nine thousand, seven hundred twenty-eight".