21775236218220 has 192 divisors, whose sum is σ = 62751839754240. Its totient is φ = 5639053099008.

The previous prime is 21775236218191. The next prime is 21775236218243. The reversal of 21775236218220 is 2281263257712.

It is a self number, because there is not a number n which added to its sum of digits gives 21775236218220.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 903637212 + ... + 903661308.

It is an arithmetic number, because the mean of its divisors is an integer number (326832498720).

Almost surely, 2^{21775236218220} is an apocalyptic number.

21775236218220 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 21775236218220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31375919877120).

21775236218220 is an abundant number, since it is smaller than the sum of its proper divisors (40976603536020).

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

21775236218220 is a wasteful number, since it uses less digits than its factorization.

21775236218220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26632 (or 26630 counting only the distinct ones).

The product of its (nonzero) digits is 1128960, while the sum is 48.

The spelling of 21775236218220 in words is "twenty-one trillion, seven hundred seventy-five billion, two hundred thirty-six million, two hundred eighteen thousand, two hundred twenty".