12215515521 has 32 divisors (see below), whose sum is σ = 17884551168. Its totient is φ = 7354907840.

The previous prime is 12215515483. The next prime is 12215515537. The reversal of 12215515521 is 12551551221.

It is a cyclic number.

It is not a de Polignac number, because 12215515521 - 2⁹ = 12215515009 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12215515561) 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, 7715896 + ... + 7717478.

It is an arithmetic number, because the mean of its divisors is an integer number (558892224).

Almost surely, 2^12215515521 is an apocalyptic number.

12215515521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12215515521 is a deficient number, since it is larger than the sum of its proper divisors (5669035647).

12215515521 is a wasteful number, since it uses less digits than its factorization.

12215515521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2981.

The product of its digits is 5000, while the sum is 30.

The spelling of 12215515521 in words is "twelve billion, two hundred fifteen million, five hundred fifteen thousand, five hundred twenty-one".