21267689 has 2 divisors, whose sum is σ = 21267690. Its totient is φ = 21267688.

The previous prime is 21267683. The next prime is 21267713. The reversal of 21267689 is 98676212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21114025 + 153664 = 4595^2 + 392^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21267689 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21267683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10633844 + 10633845.

It is an arithmetic number, because the mean of its divisors is an integer number (10633845).

Almost surely, 2^21267689 is an apocalyptic number.

It is an amenable number.

21267689 is a deficient number, since it is larger than the sum of its proper divisors (1).

21267689 is an equidigital number, since it uses as much as digits as its factorization.

21267689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72576, while the sum is 41.

The square root of 21267689 is about 4611.6904709662. The cubic root of 21267689 is about 277.0597472200.

The spelling of 21267689 in words is "twenty-one million, two hundred sixty-seven thousand, six hundred eighty-nine".