7166821 has 4 divisors (see below), whose sum is σ = 7192972. Its totient is φ = 7140672.

The previous prime is 7166813. The next prime is 7166827. The reversal of 7166821 is 1286617.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2265025 + 4901796 = 1505^2 + 2214^2 .

It is a cyclic number.

It is not a de Polignac number, because 7166821 - 2³ = 7166813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7166827) 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, 12660 + ... + 13213.

It is an arithmetic number, because the mean of its divisors is an integer number (1798243).

Almost surely, 2^7166821 is an apocalyptic number.

It is an amenable number.

7166821 is a deficient number, since it is larger than the sum of its proper divisors (26151).

7166821 is a wasteful number, since it uses less digits than its factorization.

7166821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26150.

The product of its digits is 4032, while the sum is 31.

The square root of 7166821 is about 2677.0918923339. The cubic root of 7166821 is about 192.8008092831.

The spelling of 7166821 in words is "seven million, one hundred sixty-six thousand, eight hundred twenty-one".