12215755756721 has 4 divisors (see below), whose sum is σ = 13326279007344. Its totient is φ = 11105232506100.

The previous prime is 12215755756691. The next prime is 12215755756759. The reversal of 12215755756721 is 12765755751221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 12215755756721 - 2¹⁸ = 12215755494577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12215755756621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 555261625295 + ... + 555261625316.

It is an arithmetic number, because the mean of its divisors is an integer number (3331569751836).

Almost surely, 2^{12215755756721} is an apocalyptic number.

12215755756721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12215755756721 is a deficient number, since it is larger than the sum of its proper divisors (1110523250623).

12215755756721 is a wasteful number, since it uses less digits than its factorization.

12215755756721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1110523250622.

The product of its digits is 10290000, while the sum is 56.

The spelling of 12215755756721 in words is "twelve trillion, two hundred fifteen billion, seven hundred fifty-five million, seven hundred fifty-six thousand, seven hundred twenty-one".