21321174 has 48 divisors (see below), whose sum is σ = 50692608. Its totient is φ = 5958288.

The previous prime is 21321169. The next prime is 21321187. The reversal of 21321174 is 47112312.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21321174.

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 23 ways as a sum of consecutive naturals, for example, 13047 + ... + 14589.

It is an arithmetic number, because the mean of its divisors is an integer number (1056096).

Almost surely, 2^21321174 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21321174, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25346304).

21321174 is an abundant number, since it is smaller than the sum of its proper divisors (29371434).

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

21321174 is a wasteful number, since it uses less digits than its factorization.

21321174 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1609 (or 1602 counting only the distinct ones).

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

The square root of 21321174 is about 4617.4856794580. The cubic root of 21321174 is about 277.2918071582.

Adding to 21321174 its reverse (47112312), we get a palindrome (68433486).

The spelling of 21321174 in words is "twenty-one million, three hundred twenty-one thousand, one hundred seventy-four".