21020204 has 12 divisors (see below), whose sum is σ = 37289784. Its totient is φ = 10365984.

The previous prime is 21020161. The next prime is 21020227. The reversal of 21020204 is 40202012.

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 3 ways as a sum of consecutive naturals, for example, 35702 + ... + 36285.

It is an arithmetic number, because the mean of its divisors is an integer number (3107482).

Almost surely, 2^21020204 is an apocalyptic number.

It is an amenable number.

21020204 is a deficient number, since it is larger than the sum of its proper divisors (16269580).

21020204 is a wasteful number, since it uses less digits than its factorization.

21020204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72064 (or 72062 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 11.

The square root of 21020204 is about 4584.7796021183. The cubic root of 21020204 is about 275.9808675388.

Adding to 21020204 its reverse (40202012), we get a palindrome (61222216).

The spelling of 21020204 in words is "twenty-one million, twenty thousand, two hundred four".