21100100103 has 30 divisors (see below), whose sum is σ = 33483117096. Its totient is φ = 13239263808.

The previous prime is 21100100093. The next prime is 21100100143. The reversal of 21100100103 is 30100100112.

It is not a de Polignac number, because 21100100103 - 2⁵ = 21100100071 is a prime.

It is a super-2 number, since 2×21100100103² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100100143) 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 29 ways as a sum of consecutive naturals, for example, 427275 + ... + 474092.

Almost surely, 2^21100100103 is an apocalyptic number.

21100100103 is a deficient number, since it is larger than the sum of its proper divisors (12383016993).

21100100103 is an equidigital number, since it uses as much as digits as its factorization.

21100100103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 901413 (or 901387 counting only the distinct ones).

The product of its (nonzero) digits is 6, while the sum is 9.

Adding to 21100100103 its reverse (30100100112), we get a palindrome (51200200215).

Subtracting 21100100103 from its reverse (30100100112), we obtain a palindrome (9000000009).

The spelling of 21100100103 in words is "twenty-one billion, one hundred million, one hundred thousand, one hundred three".