12171220720 has 40 divisors (see below), whose sum is σ = 29962684944. Its totient is φ = 4582106112.

The previous prime is 12171220717. The next prime is 12171220727. The reversal of 12171220720 is 2702217121.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×12171220720² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12171220727) 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, 4473354 + ... + 4476073.

Almost surely, 2^12171220720 is an apocalyptic number.

12171220720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12171220720 is an abundant number, since it is smaller than the sum of its proper divisors (17791464224).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12171220720 is a wasteful number, since it uses less digits than its factorization.

12171220720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8949457 (or 8949451 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 25.

Adding to 12171220720 its reverse (2702217121), we get a palindrome (14873437841).

The spelling of 12171220720 in words is "twelve billion, one hundred seventy-one million, two hundred twenty thousand, seven hundred twenty".