21221201118 has 128 divisors (see below), whose sum is σ = 48923481600. Its totient is φ = 6082560000.

The previous prime is 21221201117. The next prime is 21221201129. The reversal of 21221201118 is 81110212212.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21221201094 and 21221201103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221201117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 33106078 + ... + 33106718.

It is an arithmetic number, because the mean of its divisors is an integer number (382214700).

Almost surely, 2^21221201118 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21221201118, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24461740800).

21221201118 is an abundant number, since it is smaller than the sum of its proper divisors (27702280482).

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

21221201118 is a wasteful number, since it uses less digits than its factorization.

21221201118 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1018.

The product of its (nonzero) digits is 128, while the sum is 21.

The spelling of 21221201118 in words is "twenty-one billion, two hundred twenty-one million, two hundred one thousand, one hundred eighteen".