21002122170 has 48 divisors (see below), whose sum is σ = 55420541280. Its totient is φ = 5516973792.

The previous prime is 21002122159. The next prime is 21002122171. The reversal of 21002122170 is 7122120012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21002122171) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1735440 + ... + 1747499.

It is an arithmetic number, because the mean of its divisors is an integer number (1154594610).

Almost surely, 2^21002122170 is an apocalyptic number.

21002122170 is an abundant number, since it is smaller than the sum of its proper divisors (34418419110).

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

21002122170 is a wasteful number, since it uses less digits than its factorization.

21002122170 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3483019 (or 3483016 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

Adding to 21002122170 its reverse (7122120012), we get a palindrome (28124242182).

The spelling of 21002122170 in words is "twenty-one billion, two million, one hundred twenty-two thousand, one hundred seventy".