21367771 has 2 divisors, whose sum is σ = 21367772. Its totient is φ = 21367770.

The previous prime is 21367763. The next prime is 21367777. The reversal of 21367771 is 17776312.

21367771 is nontrivially palindromic in base 15.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21367771 - 2³ = 21367763 is a prime.

It is not a weakly prime, because it can be changed into another prime (21367777) 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, 10683885 + 10683886.

It is an arithmetic number, because the mean of its divisors is an integer number (10683886).

Almost surely, 2^21367771 is an apocalyptic number.

21367771 is a deficient number, since it is larger than the sum of its proper divisors (1).

21367771 is an equidigital number, since it uses as much as digits as its factorization.

21367771 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12348, while the sum is 34.

The square root of 21367771 is about 4622.5286370124. The cubic root of 21367771 is about 277.4936654128.

The spelling of 21367771 in words is "twenty-one million, three hundred sixty-seven thousand, seven hundred seventy-one".