21310207 has 2 divisors, whose sum is σ = 21310208. Its totient is φ = 21310206.

The previous prime is 21310199. The next prime is 21310243. The reversal of 21310207 is 70201312.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21310207 - 2³ = 21310199 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21310297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655103 + 10655104.

It is an arithmetic number, because the mean of its divisors is an integer number (10655104).

Almost surely, 2^21310207 is an apocalyptic number.

21310207 is a deficient number, since it is larger than the sum of its proper divisors (1).

21310207 is an equidigital number, since it uses as much as digits as its factorization.

21310207 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 21310207 is about 4616.2979756511. The cubic root of 21310207 is about 277.2442553550.

Adding to 21310207 its reverse (70201312), we get a palindrome (91511519).

The spelling of 21310207 in words is "twenty-one million, three hundred ten thousand, two hundred seven".