21031021903 has 2 divisors, whose sum is σ = 21031021904. Its totient is φ = 21031021902.

The previous prime is 21031021867. The next prime is 21031021909. The reversal of 21031021903 is 30912013012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21031021903 - 2⁹ = 21031021391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21031021909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10515510951 + 10515510952.

It is an arithmetic number, because the mean of its divisors is an integer number (10515510952).

Almost surely, 2^21031021903 is an apocalyptic number.

21031021903 is a deficient number, since it is larger than the sum of its proper divisors (1).

21031021903 is an equidigital number, since it uses as much as digits as its factorization.

21031021903 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 22.

Adding to 21031021903 its reverse (30912013012), we get a palindrome (51943034915).

The spelling of 21031021903 in words is "twenty-one billion, thirty-one million, twenty-one thousand, nine hundred three".