21051023903 has 16 divisors (see below), whose sum is σ = 26236922880. Its totient is φ = 16444917216.

The previous prime is 21051023893. The next prime is 21051023921. The reversal of 21051023903 is 30932015012.

It is not a de Polignac number, because 21051023903 - 2³⁰ = 19977282079 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21051023923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1456925 + ... + 1471302.

It is an arithmetic number, because the mean of its divisors is an integer number (1639807680).

Almost surely, 2^21051023903 is an apocalyptic number.

21051023903 is a deficient number, since it is larger than the sum of its proper divisors (5185898977).

21051023903 is a wasteful number, since it uses less digits than its factorization.

21051023903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2928326.

The product of its (nonzero) digits is 1620, while the sum is 26.

Adding to 21051023903 its reverse (30932015012), we get a palindrome (51983038915).

The spelling of 21051023903 in words is "twenty-one billion, fifty-one million, twenty-three thousand, nine hundred three".