21262289 has 2 divisors, whose sum is σ = 21262290. Its totient is φ = 21262288.

The previous prime is 21262247. The next prime is 21262301. The reversal of 21262289 is 98226212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13082689 + 8179600 = 3617^2 + 2860^2 .

It is a cyclic number.

It is not a de Polignac number, because 21262289 - 2²⁴ = 4485073 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21262229) 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, 10631144 + 10631145.

It is an arithmetic number, because the mean of its divisors is an integer number (10631145).

Almost surely, 2^21262289 is an apocalyptic number.

It is an amenable number.

21262289 is a deficient number, since it is larger than the sum of its proper divisors (1).

21262289 is an equidigital number, since it uses as much as digits as its factorization.

21262289 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 32.

The square root of 21262289 is about 4611.1049651900. The cubic root of 21262289 is about 277.0362961643.

The spelling of 21262289 in words is "twenty-one million, two hundred sixty-two thousand, two hundred eighty-nine".