21103087 has 2 divisors, whose sum is σ = 21103088. Its totient is φ = 21103086.

The previous prime is 21103081. The next prime is 21103109. The reversal of 21103087 is 78030112.

It is an a-pointer prime, because the next prime (21103109) can be obtained adding 21103087 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21103087 - 2³ = 21103079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21103081) 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, 10551543 + 10551544.

It is an arithmetic number, because the mean of its divisors is an integer number (10551544).

Almost surely, 2^21103087 is an apocalyptic number.

21103087 is a deficient number, since it is larger than the sum of its proper divisors (1).

21103087 is an equidigital number, since it uses as much as digits as its factorization.

21103087 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 21103087 is about 4593.8096390686. The cubic root of 21103087 is about 276.3431241498.

Adding to 21103087 its reverse (78030112), we get a palindrome (99133199).

Subtracting 21103087 from its reverse (78030112), we obtain a square (56927025 = 7545²).

The spelling of 21103087 in words is "twenty-one million, one hundred three thousand, eighty-seven".