21156127 has 2 divisors, whose sum is σ = 21156128. Its totient is φ = 21156126.

The previous prime is 21156077. The next prime is 21156131. The reversal of 21156127 is 72165112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21156127 - 2⁷ = 21155999 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21156227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10578063 + 10578064.

It is an arithmetic number, because the mean of its divisors is an integer number (10578064).

Almost surely, 2^21156127 is an apocalyptic number.

21156127 is a deficient number, since it is larger than the sum of its proper divisors (1).

21156127 is an equidigital number, since it uses as much as digits as its factorization.

21156127 is an evil number, because the sum of its binary digits is even.

The product of its digits is 840, while the sum is 25.

The square root of 21156127 is about 4599.5790024740. The cubic root of 21156127 is about 276.5744485480.

The spelling of 21156127 in words is "twenty-one million, one hundred fifty-six thousand, one hundred twenty-seven".