21144769 has 2 divisors, whose sum is σ = 21144770. Its totient is φ = 21144768.

The previous prime is 21144763. The next prime is 21144803. The reversal of 21144769 is 96744112.

It is an a-pointer prime, because the next prime (21144803) can be obtained adding 21144769 to its sum of digits (34).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10647169 + 10497600 = 3263^2 + 3240^2 .

It is a cyclic number.

It is not a de Polignac number, because 21144769 - 2⁵ = 21144737 is a prime.

It is a super-2 number, since 2×21144769² = 894202512126722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21144763) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10572384 + 10572385.

It is an arithmetic number, because the mean of its divisors is an integer number (10572385).

Almost surely, 2^21144769 is an apocalyptic number.

It is an amenable number.

21144769 is a deficient number, since it is larger than the sum of its proper divisors (1).

21144769 is an equidigital number, since it uses as much as digits as its factorization.

21144769 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 34.

The square root of 21144769 is about 4598.3441584988. The cubic root of 21144769 is about 276.5249452384.

The spelling of 21144769 in words is "twenty-one million, one hundred forty-four thousand, seven hundred sixty-nine".