21267161 has 2 divisors, whose sum is σ = 21267162. Its totient is φ = 21267160.

The previous prime is 21267149. The next prime is 21267227. The reversal of 21267161 is 16176212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19360000 + 1907161 = 4400^2 + 1381^2 .

It is a cyclic number.

It is not a de Polignac number, because 21267161 - 2¹⁴ = 21250777 is a prime.

It is a Chen prime.

It is a zygodrome in base 3.

It is a self number, because there is not a number n which added to its sum of digits gives 21267161.

It is not a weakly prime, because it can be changed into another prime (21267461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10633580 + 10633581.

It is an arithmetic number, because the mean of its divisors is an integer number (10633581).

Almost surely, 2^21267161 is an apocalyptic number.

It is an amenable number.

21267161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21267161 is an equidigital number, since it uses as much as digits as its factorization.

21267161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008, while the sum is 26.

The square root of 21267161 is about 4611.6332247914. The cubic root of 21267161 is about 277.0574544030.

The spelling of 21267161 in words is "twenty-one million, two hundred sixty-seven thousand, one hundred sixty-one".