7129721 has 8 divisors (see below), whose sum is σ = 7392000. Its totient is φ = 6869520.

The previous prime is 7129711. The next prime is 7129729. The reversal of 7129721 is 1279217.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 7129721 - 2¹⁰ = 7128697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7129729) 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 7 ways as a sum of consecutive naturals, for example, 10490 + ... + 11148.

It is an arithmetic number, because the mean of its divisors is an integer number (924000).

Almost surely, 2^7129721 is an apocalyptic number.

It is an amenable number.

7129721 is a deficient number, since it is larger than the sum of its proper divisors (262279).

7129721 is a wasteful number, since it uses less digits than its factorization.

7129721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1039.

The product of its digits is 1764, while the sum is 29.

The square root of 7129721 is about 2670.1537408921. The cubic root of 7129721 is about 192.4675472363.

It can be divided in two parts, 71 and 29721, that added together give a palindrome (29792).

The spelling of 7129721 in words is "seven million, one hundred twenty-nine thousand, seven hundred twenty-one".