8205841621 has 4 divisors (see below), whose sum is σ = 8209551852. Its totient is φ = 8202131392.

The previous prime is 8205841607. The next prime is 8205841643. The reversal of 8205841621 is 1261485028.

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 8148672900 + 57168721 = 90270^2 + 7561^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8205841621 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 (8205841601) 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, 1851796 + ... + 1856221.

It is an arithmetic number, because the mean of its divisors is an integer number (2052387963).

Almost surely, 2^8205841621 is an apocalyptic number.

It is an amenable number.

8205841621 is a deficient number, since it is larger than the sum of its proper divisors (3710231).

8205841621 is a wasteful number, since it uses less digits than its factorization.

8205841621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3710230.

The product of its (nonzero) digits is 30720, while the sum is 37.

The square root of 8205841621 is about 90586.1005949588. The cubic root of 8205841621 is about 2017.0084152962.

The spelling of 8205841621 in words is "eight billion, two hundred five million, eight hundred forty-one thousand, six hundred twenty-one".