8709523821 has 6 divisors (see below), whose sum is σ = 12580423310. Its totient is φ = 5806349208.

The previous prime is 8709523813. The next prime is 8709523841. The reversal of 8709523821 is 1283259078.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 7918508196 + 791015625 = 88986^2 + 28125^2 .

It is not a de Polignac number, because 8709523821 - 2³ = 8709523813 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 (8709523841) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 483862426 + ... + 483862443.

Almost surely, 2^8709523821 is an apocalyptic number.

It is an amenable number.

8709523821 is a deficient number, since it is larger than the sum of its proper divisors (3870899489).

8709523821 is a wasteful number, since it uses less digits than its factorization.

8709523821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 967724875 (or 967724872 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The square root of 8709523821 is about 93324.8296060593. The cubic root of 8709523821 is about 2057.4603306054.

The spelling of 8709523821 in words is "eight billion, seven hundred nine million, five hundred twenty-three thousand, eight hundred twenty-one".