21322170 has 64 divisors (see below), whose sum is σ = 57335040. Its totient is φ = 5638464.

The previous prime is 21322139. The next prime is 21322181. The reversal of 21322170 is 7122312.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 42139 + ... + 42641.

It is an arithmetic number, because the mean of its divisors is an integer number (895860).

Almost surely, 2^21322170 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21322170, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28667520).

21322170 is an abundant number, since it is smaller than the sum of its proper divisors (36012870).

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

21322170 is a wasteful number, since it uses less digits than its factorization.

21322170 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 676 (or 670 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21322170 is about 4617.5935291015. The cubic root of 21322170 is about 277.2961249057.

Adding to 21322170 its reverse (7122312), we get a palindrome (28444482).

The spelling of 21322170 in words is "twenty-one million, three hundred twenty-two thousand, one hundred seventy".