12115556621 has 16 divisors (see below), whose sum is σ = 14236497408. Its totient is φ = 10094025600.

The previous prime is 12115556611. The next prime is 12115556639. The reversal of 12115556621 is 12665551121.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12115556621 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12115556611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 110 + ... + 155663.

It is an arithmetic number, because the mean of its divisors is an integer number (889781088).

Almost surely, 2^12115556621 is an apocalyptic number.

It is an amenable number.

12115556621 is a deficient number, since it is larger than the sum of its proper divisors (2120940787).

12115556621 is a wasteful number, since it uses less digits than its factorization.

12115556621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156092.

The product of its digits is 18000, while the sum is 35.

The spelling of 12115556621 in words is "twelve billion, one hundred fifteen million, five hundred fifty-six thousand, six hundred twenty-one".