21143207 has 2 divisors, whose sum is σ = 21143208. Its totient is φ = 21143206.

The previous prime is 21143203. The next prime is 21143251. The reversal of 21143207 is 70234112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21143207 - 2² = 21143203 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21143201) 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 as a sum of consecutive naturals, namely, 10571603 + 10571604.

It is an arithmetic number, because the mean of its divisors is an integer number (10571604).

Almost surely, 2^21143207 is an apocalyptic number.

21143207 is a deficient number, since it is larger than the sum of its proper divisors (1).

21143207 is an equidigital number, since it uses as much as digits as its factorization.

21143207 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 21143207 is about 4598.1743116154. The cubic root of 21143207 is about 276.5181359483.

Adding to 21143207 its reverse (70234112), we get a palindrome (91377319).

The spelling of 21143207 in words is "twenty-one million, one hundred forty-three thousand, two hundred seven".