21962209 has 2 divisors, whose sum is σ = 21962210. Its totient is φ = 21962208.

The previous prime is 21962203. The next prime is 21962261. The reversal of 21962209 is 90226912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13667809 + 8294400 = 3697^2 + 2880^2 .

It is a cyclic number.

It is not a de Polignac number, because 21962209 - 2⁹ = 21961697 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21962203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10981104 + 10981105.

It is an arithmetic number, because the mean of its divisors is an integer number (10981105).

Almost surely, 2^21962209 is an apocalyptic number.

It is an amenable number.

21962209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21962209 is an equidigital number, since it uses as much as digits as its factorization.

21962209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 21962209 is about 4686.3854941735. The cubic root of 21962209 is about 280.0433988852.

The spelling of 21962209 in words is "twenty-one million, nine hundred sixty-two thousand, two hundred nine".