12205721155 has 4 divisors (see below), whose sum is σ = 14646865392. Its totient is φ = 9764576920.

The previous prime is 12205721131. The next prime is 12205721159. The reversal of 12205721155 is 55112750221.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 12205721155 - 2¹¹ = 12205719107 is a prime.

It is a super-2 number, since 2×12205721155² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12205721159) 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, 1220572111 + ... + 1220572120.

It is an arithmetic number, because the mean of its divisors is an integer number (3661716348).

Almost surely, 2^12205721155 is an apocalyptic number.

12205721155 is a deficient number, since it is larger than the sum of its proper divisors (2441144237).

12205721155 is an equidigital number, since it uses as much as digits as its factorization.

12205721155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2441144236.

The product of its (nonzero) digits is 7000, while the sum is 31.

The spelling of 12205721155 in words is "twelve billion, two hundred five million, seven hundred twenty-one thousand, one hundred fifty-five".