7021728 has 168 divisors, whose sum is σ = 24238368. Its totient is φ = 1959552.

The previous prime is 7021723. The next prime is 7021759. The reversal of 7021728 is 8271207.

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

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7021723) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 163275 + ... + 163317.

It is an arithmetic number, because the mean of its divisors is an integer number (144276).

Almost surely, 2^7021728 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 7021728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12119184).

7021728 is an abundant number, since it is smaller than the sum of its proper divisors (17216640).

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

7021728 is an equidigital number, since it uses as much as digits as its factorization.

7021728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78 (or 55 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 27.

The square root of 7021728 is about 2649.8543356192. The cubic root of 7021728 is about 191.4908384567.

The spelling of 7021728 in words is "seven million, twenty-one thousand, seven hundred twenty-eight".