21971927 has 2 divisors, whose sum is σ = 21971928. Its totient is φ = 21971926.

The previous prime is 21971903. The next prime is 21971933. The reversal of 21971927 is 72917912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21971927 - 2¹⁰ = 21970903 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21971947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10985963 + 10985964.

It is an arithmetic number, because the mean of its divisors is an integer number (10985964).

Almost surely, 2^21971927 is an apocalyptic number.

21971927 is a deficient number, since it is larger than the sum of its proper divisors (1).

21971927 is an equidigital number, since it uses as much as digits as its factorization.

21971927 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15876, while the sum is 38.

The square root of 21971927 is about 4687.4222126879. The cubic root of 21971927 is about 280.0846980163.

The spelling of 21971927 in words is "twenty-one million, nine hundred seventy-one thousand, nine hundred twenty-seven".