21331436 has 24 divisors (see below), whose sum is σ = 42957600. Its totient is φ = 9078912.

The previous prime is 21331399. The next prime is 21331451. The reversal of 21331436 is 63413312.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1616 + ... + 6728.

It is an arithmetic number, because the mean of its divisors is an integer number (1789900).

Almost surely, 2^21331436 is an apocalyptic number.

It is an amenable number.

21331436 is an abundant number, since it is smaller than the sum of its proper divisors (21626164).

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

21331436 is a wasteful number, since it uses less digits than its factorization.

21331436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5273 (or 5271 counting only the distinct ones).

The product of its digits is 1296, while the sum is 23.

The square root of 21331436 is about 4618.5967565918. The cubic root of 21331436 is about 277.3362873874.

Adding to 21331436 its reverse (63413312), we get a palindrome (84744748).

The spelling of 21331436 in words is "twenty-one million, three hundred thirty-one thousand, four hundred thirty-six".