21992771 has 2 divisors, whose sum is σ = 21992772. Its totient is φ = 21992770.

The previous prime is 21992723. The next prime is 21992797. The reversal of 21992771 is 17729912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21992771 - 2¹⁴ = 21976387 is a prime.

It is a Chen prime.

It is equal to p_1388846 and since 21992771 and 1388846 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21292771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10996385 + 10996386.

It is an arithmetic number, because the mean of its divisors is an integer number (10996386).

Almost surely, 2^21992771 is an apocalyptic number.

21992771 is a deficient number, since it is larger than the sum of its proper divisors (1).

21992771 is an equidigital number, since it uses as much as digits as its factorization.

21992771 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 21992771 is about 4689.6450825196. The cubic root of 21992771 is about 280.1732388817.

The spelling of 21992771 in words is "twenty-one million, nine hundred ninety-two thousand, seven hundred seventy-one".