21308107 has 2 divisors, whose sum is σ = 21308108. Its totient is φ = 21308106.

The previous prime is 21308081. The next prime is 21308137. The reversal of 21308107 is 70180312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21308107 - 2²³ = 12919499 is a prime.

It is a super-3 number, since 3×21308107³ (a number of 23 digits) contains 333 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21308137) 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, 10654053 + 10654054.

It is an arithmetic number, because the mean of its divisors is an integer number (10654054).

Almost surely, 2^21308107 is an apocalyptic number.

21308107 is a deficient number, since it is larger than the sum of its proper divisors (1).

21308107 is an equidigital number, since it uses as much as digits as its factorization.

21308107 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 21308107 is about 4616.0705150593. The cubic root of 21308107 is about 277.2351481064.

Adding to 21308107 its reverse (70180312), we get a palindrome (91488419).

The spelling of 21308107 in words is "twenty-one million, three hundred eight thousand, one hundred seven".