21204107 has 2 divisors, whose sum is σ = 21204108. Its totient is φ = 21204106.

The previous prime is 21204077. The next prime is 21204119. The reversal of 21204107 is 70140212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21204107 - 2⁸ = 21203851 is a prime.

It is a super-2 number, since 2×21204107² = 899228307334898, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21204607) 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, 10602053 + 10602054.

It is an arithmetic number, because the mean of its divisors is an integer number (10602054).

Almost surely, 2^21204107 is an apocalyptic number.

21204107 is a deficient number, since it is larger than the sum of its proper divisors (1).

21204107 is an equidigital number, since it uses as much as digits as its factorization.

21204107 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 21204107 is about 4604.7917433908. The cubic root of 21204107 is about 276.7833718377.

Adding to 21204107 its reverse (70140212), we get a palindrome (91344319).

The spelling of 21204107 in words is "twenty-one million, two hundred four thousand, one hundred seven".