21031222170 has 256 divisors, whose sum is σ = 63832412160. Its totient is φ = 4326690816.

The previous prime is 21031222141. The next prime is 21031222171. The reversal of 21031222170 is 7122213012.

21031222170 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21031222171) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 6346434 + ... + 6349746.

It is an arithmetic number, because the mean of its divisors is an integer number (249345360).

Almost surely, 2^21031222170 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21031222170, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31916206080).

21031222170 is an abundant number, since it is smaller than the sum of its proper divisors (42801189990).

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

21031222170 is a wasteful number, since it uses less digits than its factorization.

21031222170 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3429.

The product of its (nonzero) digits is 336, while the sum is 21.

Adding to 21031222170 its reverse (7122213012), we get a palindrome (28153435182).

The spelling of 21031222170 in words is "twenty-one billion, thirty-one million, two hundred twenty-two thousand, one hundred seventy".