8215518821 has 8 divisors (see below), whose sum is σ = 8703163584. Its totient is φ = 7728360640.

The previous prime is 8215518797. The next prime is 8215518823. The reversal of 8215518821 is 1288155128.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 8215518821 - 2⁶ = 8215518757 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 (8215518823) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 86585 + ... + 154686.

It is an arithmetic number, because the mean of its divisors is an integer number (1087895448).

Almost surely, 2^8215518821 is an apocalyptic number.

It is an amenable number.

8215518821 is a deficient number, since it is larger than the sum of its proper divisors (487644763).

8215518821 is a wasteful number, since it uses less digits than its factorization.

8215518821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243291.

The product of its digits is 51200, while the sum is 41.

The square root of 8215518821 is about 90639.4992318470. The cubic root of 8215518821 is about 2017.8009939983.

The spelling of 8215518821 in words is "eight billion, two hundred fifteen million, five hundred eighteen thousand, eight hundred twenty-one".