7165821 has 16 divisors (see below), whose sum is σ = 10531136. Its totient is φ = 4306176.

The previous prime is 7165787. The next prime is 7165859. The reversal of 7165821 is 1285617.

It is not a de Polignac number, because 7165821 - 2⁶ = 7165757 is a prime.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

7165821 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7165021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 460 + ... + 3813.

It is an arithmetic number, because the mean of its divisors is an integer number (658196).

Almost surely, 2^7165821 is an apocalyptic number.

It is an amenable number.

7165821 is a deficient number, since it is larger than the sum of its proper divisors (3365315).

7165821 is a wasteful number, since it uses less digits than its factorization.

7165821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4332.

The product of its digits is 3360, while the sum is 30.

The square root of 7165821 is about 2676.9051159875. The cubic root of 7165821 is about 192.7918415796.

The spelling of 7165821 in words is "seven million, one hundred sixty-five thousand, eight hundred twenty-one".