21043402 has 8 divisors (see below), whose sum is σ = 31618116. Its totient is φ = 10504032.

The previous prime is 21043391. The next prime is 21043409. The reversal of 21043402 is 20434012.

It can be written as a sum of positive squares in 2 ways, for example, as 18224361 + 2819041 = 4269^2 + 1679^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21043409) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7293 + ... + 9760.

Almost surely, 2^21043402 is an apocalyptic number.

21043402 is a deficient number, since it is larger than the sum of its proper divisors (10574714).

21043402 is a wasteful number, since it uses less digits than its factorization.

21043402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17672.

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21043402 is about 4587.3087971053. The cubic root of 21043402 is about 276.0823548260.

Adding to 21043402 its reverse (20434012), we get a palindrome (41477414).

The spelling of 21043402 in words is "twenty-one million, forty-three thousand, four hundred two".