21204162 has 72 divisors (see below), whose sum is σ = 55352700. Its totient is φ = 5842368.

The previous prime is 21204143. The next prime is 21204199. The reversal of 21204162 is 26140212.

It can be written as a sum of positive squares in 2 ways, for example, as 21150801 + 53361 = 4599^2 + 231^2 .

It is a super-2 number, since 2×21204162² = 899232972244488, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 25164 + ... + 25992.

Almost surely, 2^21204162 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21204162, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27676350).

21204162 is an abundant number, since it is smaller than the sum of its proper divisors (34148538).

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

21204162 is a wasteful number, since it uses less digits than its factorization.

21204162 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 880 (or 870 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21204162 is about 4604.7977154268. The cubic root of 21204162 is about 276.7836111478.

Adding to 21204162 its reverse (26140212), we get a palindrome (47344374).

The spelling of 21204162 in words is "twenty-one million, two hundred four thousand, one hundred sixty-two".