7171921 has 4 divisors (see below), whose sum is σ = 7179700. Its totient is φ = 7164144.

The previous prime is 7171891. The next prime is 7171933. The reversal of 7171921 is 1291717.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 4060225 + 3111696 = 2015^2 + 1764^2 .

It is a cyclic number.

It is not a de Polignac number, because 7171921 - 2⁷ = 7171793 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 7171921.

It is not an unprimeable number, because it can be changed into a prime (7171951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2286 + ... + 4423.

It is an arithmetic number, because the mean of its divisors is an integer number (1794925).

Almost surely, 2^7171921 is an apocalyptic number.

It is an amenable number.

7171921 is a deficient number, since it is larger than the sum of its proper divisors (7779).

7171921 is a wasteful number, since it uses less digits than its factorization.

7171921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7778.

The product of its digits is 882, while the sum is 28.

The square root of 7171921 is about 2678.0442490743. The cubic root of 7171921 is about 192.8465315998.

The spelling of 7171921 in words is "seven million, one hundred seventy-one thousand, nine hundred twenty-one".