21304642 has 8 divisors (see below), whose sum is σ = 32316300. Its totient is φ = 10532544.

The previous prime is 21304639. The next prime is 21304667. The reversal of 21304642 is 24640312.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 17065161 + 4239481 = 4131^2 + 2059^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59667 + ... + 60022.

Almost surely, 2^21304642 is an apocalyptic number.

21304642 is a deficient number, since it is larger than the sum of its proper divisors (11011658).

21304642 is a wasteful number, since it uses less digits than its factorization.

21304642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119780.

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 21304642 is about 4615.6951805768. The cubic root of 21304642 is about 277.2201198378.

Adding to 21304642 its reverse (24640312), we get a palindrome (45944954).

The spelling of 21304642 in words is "twenty-one million, three hundred four thousand, six hundred forty-two".