21891127 has 2 divisors, whose sum is σ = 21891128. Its totient is φ = 21891126.

The previous prime is 21891119. The next prime is 21891157. The reversal of 21891127 is 72119812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21891127 - 2³ = 21891119 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21891157) 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, 10945563 + 10945564.

It is an arithmetic number, because the mean of its divisors is an integer number (10945564).

Almost surely, 2^21891127 is an apocalyptic number.

21891127 is a deficient number, since it is larger than the sum of its proper divisors (1).

21891127 is an equidigital number, since it uses as much as digits as its factorization.

21891127 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2016, while the sum is 31.

The square root of 21891127 is about 4678.7954646469. The cubic root of 21891127 is about 279.7409466246.

The spelling of 21891127 in words is "twenty-one million, eight hundred ninety-one thousand, one hundred twenty-seven".