21355667 has 2 divisors, whose sum is σ = 21355668. Its totient is φ = 21355666.

The previous prime is 21355657. The next prime is 21355669. The reversal of 21355667 is 76655312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21355667 - 2¹² = 21351571 is a prime.

Together with 21355669, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21355669) 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, 10677833 + 10677834.

It is an arithmetic number, because the mean of its divisors is an integer number (10677834).

Almost surely, 2^21355667 is an apocalyptic number.

21355667 is a deficient number, since it is larger than the sum of its proper divisors (1).

21355667 is an equidigital number, since it uses as much as digits as its factorization.

21355667 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 37800, while the sum is 35.

The square root of 21355667 is about 4621.2192114203. The cubic root of 21355667 is about 277.4412591085.

It can be divided in two parts, 21355 and 667, that added together give a palindrome (22022).

The spelling of 21355667 in words is "twenty-one million, three hundred fifty-five thousand, six hundred sixty-seven".