21110839 has 2 divisors, whose sum is σ = 21110840. Its totient is φ = 21110838.

The previous prime is 21110833. The next prime is 21110861. The reversal of 21110839 is 93801112.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21110839 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21110833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555419 + 10555420.

It is an arithmetic number, because the mean of its divisors is an integer number (10555420).

Almost surely, 2^21110839 is an apocalyptic number.

21110839 is a deficient number, since it is larger than the sum of its proper divisors (1).

21110839 is an equidigital number, since it uses as much as digits as its factorization.

21110839 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 21110839 is about 4594.6533057457. The cubic root of 21110839 is about 276.3769572669.

The spelling of 21110839 in words is "twenty-one million, one hundred ten thousand, eight hundred thirty-nine".