21043316 has 24 divisors (see below), whose sum is σ = 42415296. Its totient is φ = 8948160.

The previous prime is 21043313. The next prime is 21043339. The reversal of 21043316 is 61334012.

It is a super-2 number, since 2×21043316² = 885642296551712, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21043313) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 800 + ... + 6536.

It is an arithmetic number, because the mean of its divisors is an integer number (1767304).

Almost surely, 2^21043316 is an apocalyptic number.

It is an amenable number.

21043316 is an abundant number, since it is smaller than the sum of its proper divisors (21371980).

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

21043316 is a wasteful number, since it uses less digits than its factorization.

21043316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5879 (or 5877 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 21043316 is about 4587.2994234081. The cubic root of 21043316 is about 276.0819787285.

Adding to 21043316 its reverse (61334012), we get a palindrome (82377328).

The spelling of 21043316 in words is "twenty-one million, forty-three thousand, three hundred sixteen".