8219215521 has 36 divisors (see below), whose sum is σ = 13353163824. Its totient is φ = 4865469840.

The previous prime is 8219215517. The next prime is 8219215603. The reversal of 8219215521 is 1255129128.

8219215521 is a `hidden beast` number, since 82 + 1 + 9 + 21 + 552 + 1 = 666.

It is not a de Polignac number, because 8219215521 - 2² = 8219215517 is a prime.

It is not an unprimeable number, because it can be changed into a prime (8219211521) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 40935 + ... + 134588.

Almost surely, 2^8219215521 is an apocalyptic number.

It is an amenable number.

8219215521 is a deficient number, since it is larger than the sum of its proper divisors (5133948303).

8219215521 is a wasteful number, since it uses less digits than its factorization.

8219215521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175594 (or 175580 counting only the distinct ones).

The product of its digits is 14400, while the sum is 36.

The square root of 8219215521 is about 90659.8892620105. The cubic root of 8219215521 is about 2018.1035955576.

The spelling of 8219215521 in words is "eight billion, two hundred nineteen million, two hundred fifteen thousand, five hundred twenty-one".