21065207 has 2 divisors, whose sum is σ = 21065208. Its totient is φ = 21065206.

The previous prime is 21065201. The next prime is 21065273. The reversal of 21065207 is 70256012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21065207 - 2²⁰ = 20016631 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21065201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10532603 + 10532604.

It is an arithmetic number, because the mean of its divisors is an integer number (10532604).

Almost surely, 2^21065207 is an apocalyptic number.

21065207 is a deficient number, since it is larger than the sum of its proper divisors (1).

21065207 is an equidigital number, since it uses as much as digits as its factorization.

21065207 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 21065207 is about 4589.6848475685. The cubic root of 21065207 is about 276.1776799967.

The spelling of 21065207 in words is "twenty-one million, sixty-five thousand, two hundred seven".