21123010103 has 4 divisors (see below), whose sum is σ = 22747857048. Its totient is φ = 19498163160.

The previous prime is 21123010081. The next prime is 21123010159. The reversal of 21123010103 is 30101032112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21123010103 - 2¹⁰ = 21123009079 is a prime.

It is a super-2 number, since 2×21123010103² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123010003) 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 3 ways as a sum of consecutive naturals, for example, 812423453 + ... + 812423478.

It is an arithmetic number, because the mean of its divisors is an integer number (5686964262).

Almost surely, 2^21123010103 is an apocalyptic number.

21123010103 is a deficient number, since it is larger than the sum of its proper divisors (1624846945).

21123010103 is a wasteful number, since it uses less digits than its factorization.

21123010103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1624846944.

The product of its (nonzero) digits is 36, while the sum is 14.

Adding to 21123010103 its reverse (30101032112), we get a palindrome (51224042215).

It can be divided in two parts, 2112 and 3010103, that multiplied together give a palindrome (6357337536).

The spelling of 21123010103 in words is "twenty-one billion, one hundred twenty-three million, ten thousand, one hundred three".