21872423618820 has 672 divisors, whose sum is σ = 72638316850176. Its totient is φ = 5522409446400.

The previous prime is 21872423618783. The next prime is 21872423618887. The reversal of 21872423618820 is 2881632427812.

It is a happy number.

21872423618820 is a `hidden beast` number, since 2 + 1 + 87 + 2 + 423 + 61 + 8 + 82 + 0 = 666.

It is a super-2 number, since 2×21872423618820² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 223 ways as a sum of consecutive naturals, for example, 5431441647 + ... + 5431445673.

It is an arithmetic number, because the mean of its divisors is an integer number (108092733408).

Almost surely, 2^{21872423618820} is an apocalyptic number.

21872423618820 is a gapful number since it is divisible by the number (20) 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 21872423618820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36319158425088).

21872423618820 is an abundant number, since it is smaller than the sum of its proper divisors (50765893231356).

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

21872423618820 is a wasteful number, since it uses less digits than its factorization.

21872423618820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4343 (or 4326 counting only the distinct ones).

The product of its (nonzero) digits is 4128768, while the sum is 54.

The spelling of 21872423618820 in words is "twenty-one trillion, eight hundred seventy-two billion, four hundred twenty-three million, six hundred eighteen thousand, eight hundred twenty".