21000269 has 2 divisors, whose sum is σ = 21000270. Its totient is φ = 21000268.

The previous prime is 21000251. The next prime is 21000277. The reversal of 21000269 is 96200012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13410244 + 7590025 = 3662^2 + 2755^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000269 - 2¹⁶ = 20934733 is a prime.

It is a super-2 number, since 2×21000269² = 882022596144722, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21000269.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500134 + 10500135.

It is an arithmetic number, because the mean of its divisors is an integer number (10500135).

Almost surely, 2^21000269 is an apocalyptic number.

It is an amenable number.

21000269 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000269 is an equidigital number, since it uses as much as digits as its factorization.

21000269 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 21000269 is about 4582.6050451681. The cubic root of 21000269 is about 275.8935956499.

The spelling of 21000269 in words is "twenty-one million, two hundred sixty-nine", and thus it is an aban number.