21127727 has 2 divisors, whose sum is σ = 21127728. Its totient is φ = 21127726.

The previous prime is 21127721. The next prime is 21127759. The reversal of 21127727 is 72772112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21127727 - 2¹² = 21123631 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21127727.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21127721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10563863 + 10563864.

It is an arithmetic number, because the mean of its divisors is an integer number (10563864).

Almost surely, 2^21127727 is an apocalyptic number.

21127727 is a deficient number, since it is larger than the sum of its proper divisors (1).

21127727 is an equidigital number, since it uses as much as digits as its factorization.

21127727 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2744, while the sum is 29.

The square root of 21127727 is about 4596.4907266305. The cubic root of 21127727 is about 276.4506352167.

Adding to 21127727 its reverse (72772112), we get a palindrome (93899839).

The spelling of 21127727 in words is "twenty-one million, one hundred twenty-seven thousand, seven hundred twenty-seven".