21127969 has 2 divisors, whose sum is σ = 21127970. Its totient is φ = 21127968.

The previous prime is 21127963. The next prime is 21127987. The reversal of 21127969 is 96972112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20250000 + 877969 = 4500^2 + 937^2 .

It is a cyclic number.

It is not a de Polignac number, because 21127969 - 2¹⁵ = 21095201 is a prime.

It is a super-2 number, since 2×21127969² = 892782148129922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21127963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10563984 + 10563985.

It is an arithmetic number, because the mean of its divisors is an integer number (10563985).

Almost surely, 2^21127969 is an apocalyptic number.

It is an amenable number.

21127969 is a deficient number, since it is larger than the sum of its proper divisors (1).

21127969 is an equidigital number, since it uses as much as digits as its factorization.

21127969 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13608, while the sum is 37.

The square root of 21127969 is about 4596.5170509855. The cubic root of 21127969 is about 276.4516907143.

The spelling of 21127969 in words is "twenty-one million, one hundred twenty-seven thousand, nine hundred sixty-nine".