21021110207 has 4 divisors (see below), whose sum is σ = 21039830040. Its totient is φ = 21002390376.

The previous prime is 21021110197. The next prime is 21021110239. The reversal of 21021110207 is 70201112012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21021110207 - 2²² = 21016915903 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021112207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9358232 + ... + 9360477.

It is an arithmetic number, because the mean of its divisors is an integer number (5259957510).

Almost surely, 2^21021110207 is an apocalyptic number.

21021110207 is a deficient number, since it is larger than the sum of its proper divisors (18719833).

21021110207 is a wasteful number, since it uses less digits than its factorization.

21021110207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18719832.

The product of its (nonzero) digits is 56, while the sum is 17.

Adding to 21021110207 its reverse (70201112012), we get a palindrome (91222222219).

The spelling of 21021110207 in words is "twenty-one billion, twenty-one million, one hundred ten thousand, two hundred seven".