21101903 has 2 divisors, whose sum is σ = 21101904. Its totient is φ = 21101902.

The previous prime is 21101887. The next prime is 21101909. The reversal of 21101903 is 30910112.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21101903 - 2⁴ = 21101887 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21101909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550951 + 10550952.

It is an arithmetic number, because the mean of its divisors is an integer number (10550952).

Almost surely, 2^21101903 is an apocalyptic number.

21101903 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101903 is an equidigital number, since it uses as much as digits as its factorization.

21101903 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54, while the sum is 17.

The square root of 21101903 is about 4593.6807681858. The cubic root of 21101903 is about 276.3379559268.

The spelling of 21101903 in words is "twenty-one million, one hundred one thousand, nine hundred three".