21210004 has 24 divisors (see below), whose sum is σ = 39616640. Its totient is φ = 9906624.

The previous prime is 21209963. The next prime is 21210011. The reversal of 21210004 is 40001212.

It is a congruent 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 7 ways as a sum of consecutive naturals, for example, 3637 + ... + 7459.

Almost surely, 2^21210004 is an apocalyptic number.

It is an amenable number.

21210004 is a deficient number, since it is larger than the sum of its proper divisors (18406636).

21210004 is a wasteful number, since it uses less digits than its factorization.

21210004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3919 (or 3917 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 21210004 is about 4605.4320101376. The cubic root of 21210004 is about 276.8090278778.

Adding to 21210004 its reverse (40001212), we get a palindrome (61211216).

The spelling of 21210004 in words is "twenty-one million, two hundred ten thousand, four".