21204626 has 32 divisors (see below), whose sum is σ = 34760880. Its totient is φ = 9676800.

The previous prime is 21204619. The next prime is 21204641. The reversal of 21204626 is 62640212.

It can be written as a sum of positive squares in 8 ways, for example, as 12496225 + 8708401 = 3535^2 + 2951^2 .

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87866 + ... + 88106.

Almost surely, 2^21204626 is an apocalyptic number.

21204626 is a deficient number, since it is larger than the sum of its proper divisors (13556254).

21204626 is a wasteful number, since it uses less digits than its factorization.

21204626 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350.

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 21204626 is about 4604.8480973861. The cubic root of 21204626 is about 276.7856300385.

Adding to 21204626 its reverse (62640212), we get a palindrome (83844838).

The spelling of 21204626 in words is "twenty-one million, two hundred four thousand, six hundred twenty-six".