21210207 has 8 divisors (see below), whose sum is σ = 28882176. Its totient is φ = 13839192.

The previous prime is 21210197. The next prime is 21210221. The reversal of 21210207 is 70201212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21210207 - 2¹⁹ = 20685919 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75073 + ... + 75354.

It is an arithmetic number, because the mean of its divisors is an integer number (3610272).

Almost surely, 2^21210207 is an apocalyptic number.

21210207 is a deficient number, since it is larger than the sum of its proper divisors (7671969).

21210207 is a wasteful number, since it uses less digits than its factorization.

21210207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150477.

The product of its (nonzero) digits is 56, while the sum is 15.

The square root of 21210207 is about 4605.4540492768. The cubic root of 21210207 is about 276.8099109839.

Adding to 21210207 its reverse (70201212), we get a palindrome (91411419).

The spelling of 21210207 in words is "twenty-one million, two hundred ten thousand, two hundred seven".