8537821821 has 32 divisors (see below), whose sum is σ = 13854499200. Its totient is φ = 5172330240.

The previous prime is 8537821819. The next prime is 8537821841. The reversal of 8537821821 is 1281287358.

8537821821 is a `hidden beast` number, since 8 + 537 + 82 + 18 + 21 = 666.

It is not a de Polignac number, because 8537821821 - 2¹ = 8537821819 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8537821841) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 307395 + ... + 334016.

It is an arithmetic number, because the mean of its divisors is an integer number (432953100).

Almost surely, 2^8537821821 is an apocalyptic number.

It is an amenable number.

8537821821 is a deficient number, since it is larger than the sum of its proper divisors (5316677379).

8537821821 is a wasteful number, since it uses less digits than its factorization.

8537821821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 641466 (or 641460 counting only the distinct ones).

The product of its digits is 215040, while the sum is 45.

The square root of 8537821821 is about 92400.3345286152. The cubic root of 8537821821 is about 2043.8500455023.

The spelling of 8537821821 in words is "eight billion, five hundred thirty-seven million, eight hundred twenty-one thousand, eight hundred twenty-one".