8145821 has 4 divisors (see below), whose sum is σ = 8156700. Its totient is φ = 8134944.

The previous prime is 8145811. The next prime is 8145827. The reversal of 8145821 is 1285418.

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 4778596 + 3367225 = 2186^2 + 1835^2 .

It is a cyclic number.

It is not a de Polignac number, because 8145821 - 2¹⁸ = 7883677 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8145827) 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, 4226 + ... + 5843.

It is an arithmetic number, because the mean of its divisors is an integer number (2039175).

Almost surely, 2^8145821 is an apocalyptic number.

It is an amenable number.

8145821 is a deficient number, since it is larger than the sum of its proper divisors (10879).

8145821 is a wasteful number, since it uses less digits than its factorization.

8145821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10878.

The product of its digits is 2560, while the sum is 29.

The square root of 8145821 is about 2854.0884709483. The cubic root of 8145821 is about 201.2078656182.

The spelling of 8145821 in words is "eight million, one hundred forty-five thousand, eight hundred twenty-one".