21208127 has 2 divisors, whose sum is σ = 21208128. Its totient is φ = 21208126.

The previous prime is 21208097. The next prime is 21208133. The reversal of 21208127 is 72180212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21208127 - 2⁶ = 21208063 is a prime.

It is a super-3 number, since 3×21208127³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21208157) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10604063 + 10604064.

It is an arithmetic number, because the mean of its divisors is an integer number (10604064).

Almost surely, 2^21208127 is an apocalyptic number.

21208127 is a deficient number, since it is larger than the sum of its proper divisors (1).

21208127 is an equidigital number, since it uses as much as digits as its factorization.

21208127 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 21208127 is about 4605.2282245292. The cubic root of 21208127 is about 276.8008621419.

Adding to 21208127 its reverse (72180212), we get a palindrome (93388339).

The spelling of 21208127 in words is "twenty-one million, two hundred eight thousand, one hundred twenty-seven".