12178221640 has 64 divisors (see below), whose sum is σ = 29631515760. Its totient is φ = 4477870080.

The previous prime is 12178221637. The next prime is 12178221641. The reversal of 12178221640 is 4612287121.

It can be written as a sum of positive squares in 8 ways, for example, as 6519270564 + 5658951076 = 80742^2 + 75226^2 .

It is a junction number, because it is equal to n+sod(n) for n = 12178221596 and 12178221605.

It is not an unprimeable number, because it can be changed into a prime (12178221641) 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, 76732 + ... + 173908.

Almost surely, 2^12178221640 is an apocalyptic number.

12178221640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 12178221640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14815757880).

12178221640 is an abundant number, since it is smaller than the sum of its proper divisors (17453294120).

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

12178221640 is a wasteful number, since it uses less digits than its factorization.

12178221640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97442 (or 97438 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 34.

The spelling of 12178221640 in words is "twelve billion, one hundred seventy-eight million, two hundred twenty-one thousand, six hundred forty".