7286821 has 4 divisors (see below), whose sum is σ = 7303500. Its totient is φ = 7270144.

The previous prime is 7286813. The next prime is 7286831. The reversal of 7286821 is 1286827.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1286827 = 23 ⋅55949.

It can be written as a sum of positive squares in 2 ways, for example, as 6100900 + 1185921 = 2470^2 + 1089^2 .

It is a cyclic number.

It is not a de Polignac number, because 7286821 - 2³ = 7286813 is a prime.

It is a Duffinian number.

7286821 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7286831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7666 + ... + 8563.

It is an arithmetic number, because the mean of its divisors is an integer number (1825875).

Almost surely, 2^7286821 is an apocalyptic number.

It is an amenable number.

7286821 is a deficient number, since it is larger than the sum of its proper divisors (16679).

7286821 is a wasteful number, since it uses less digits than its factorization.

7286821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16678.

The product of its digits is 10752, while the sum is 34.

The square root of 7286821 is about 2699.4112321023. The cubic root of 7286821 is about 193.8709330342.

The spelling of 7286821 in words is "seven million, two hundred eighty-six thousand, eight hundred twenty-one".