21103139 has 2 divisors, whose sum is σ = 21103140. Its totient is φ = 21103138.

The previous prime is 21103127. The next prime is 21103177. The reversal of 21103139 is 93130112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21103139 - 2⁴ = 21103123 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21103139.

It is not a weakly prime, because it can be changed into another prime (21103109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551569 + 10551570.

It is an arithmetic number, because the mean of its divisors is an integer number (10551570).

Almost surely, 2^21103139 is an apocalyptic number.

21103139 is a deficient number, since it is larger than the sum of its proper divisors (1).

21103139 is an equidigital number, since it uses as much as digits as its factorization.

21103139 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 162, while the sum is 20.

The square root of 21103139 is about 4593.8152988556. The cubic root of 21103139 is about 276.3433511281.

The spelling of 21103139 in words is "twenty-one million, one hundred three thousand, one hundred thirty-nine".