21205006 has 16 divisors (see below), whose sum is σ = 32457600. Its totient is φ = 10388088.

The previous prime is 21204949. The next prime is 21205021. The reversal of 21205006 is 60050212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22615 + ... + 23533.

It is an arithmetic number, because the mean of its divisors is an integer number (2028600).

Almost surely, 2^21205006 is an apocalyptic number.

21205006 is a deficient number, since it is larger than the sum of its proper divisors (11252594).

21205006 is a wasteful number, since it uses less digits than its factorization.

21205006 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1143.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21205006 is about 4604.8893580628. The cubic root of 21205006 is about 276.7872834185.

Adding to 21205006 its reverse (60050212), we get a palindrome (81255218).

The spelling of 21205006 in words is "twenty-one million, two hundred five thousand, six".