8915821 has 4 divisors (see below), whose sum is σ = 9062044. Its totient is φ = 8769600.

The previous prime is 8915801. The next prime is 8915831. The reversal of 8915821 is 1285198.

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 2937796 + 5978025 = 1714^2 + 2445^2 .

It is a cyclic number.

It is not a de Polignac number, because 8915821 - 2¹⁵ = 8883053 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 (8915801) 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, 73020 + ... + 73141.

It is an arithmetic number, because the mean of its divisors is an integer number (2265511).

Almost surely, 2^8915821 is an apocalyptic number.

It is an amenable number.

8915821 is a deficient number, since it is larger than the sum of its proper divisors (146223).

8915821 is a wasteful number, since it uses less digits than its factorization.

8915821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146222.

The product of its digits is 5760, while the sum is 34.

The square root of 8915821 is about 2985.9372063056. The cubic root of 8915821 is about 207.3578336196.

The spelling of 8915821 in words is "eight million, nine hundred fifteen thousand, eight hundred twenty-one".