12191826420 has 144 divisors (see below), whose sum is σ = 40112746128. Its totient is φ = 2985246720.

The previous prime is 12191826401. The next prime is 12191826467. The reversal of 12191826420 is 2462819121.

12191826420 is a `hidden beast` number, since 1 + 2 + 1 + 9 + 1 + 8 + 2 + 642 + 0 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 15586704 + 12176239716 = 3948^2 + 110346^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 76872 + ... + 174048.

It is an arithmetic number, because the mean of its divisors is an integer number (278560737).

Almost surely, 2^12191826420 is an apocalyptic number.

12191826420 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 12191826420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20056373064).

12191826420 is an abundant number, since it is smaller than the sum of its proper divisors (27920919708).

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

12191826420 is a wasteful number, since it uses less digits than its factorization.

12191826420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97250 (or 97245 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The spelling of 12191826420 in words is "twelve billion, one hundred ninety-one million, eight hundred twenty-six thousand, four hundred twenty".