20121843456 has 432 divisors, whose sum is σ = 68769398880. Its totient is φ = 5578260480.

The previous prime is 20121843451. The next prime is 20121843479. The reversal of 20121843456 is 65434812102.

It is a happy number.

20121843456 is a `hidden beast` number, since 2 + 0 + 1 + 218 + 434 + 5 + 6 = 666.

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

It is a self number, because there is not a number n which added to its sum of digits gives 20121843456.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121843451) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 51726910 + ... + 51727298.

Almost surely, 2^20121843456 is an apocalyptic number.

20121843456 is a gapful number since it is divisible by the number (26) 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 20121843456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34384699440).

20121843456 is an abundant number, since it is smaller than the sum of its proper divisors (48647555424).

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

20121843456 is a wasteful number, since it uses less digits than its factorization.

20121843456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 592 (or 575 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The spelling of 20121843456 in words is "twenty billion, one hundred twenty-one million, eight hundred forty-three thousand, four hundred fifty-six".