21001001103 has 12 divisors (see below), whose sum is σ = 30718764960. Its totient is φ = 13823443296.

The previous prime is 21001001053. The next prime is 21001001107. The reversal of 21001001103 is 30110010012.

It is not a de Polignac number, because 21001001103 - 2¹⁰ = 21001000079 is a prime.

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 (21001001107) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14767926 + ... + 14769347.

It is an arithmetic number, because the mean of its divisors is an integer number (2559897080).

Almost surely, 2^21001001103 is an apocalyptic number.

21001001103 is a deficient number, since it is larger than the sum of its proper divisors (9717763857).

21001001103 is a wasteful number, since it uses less digits than its factorization.

21001001103 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29537358 (or 29537355 counting only the distinct ones).

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

Adding to 21001001103 its reverse (30110010012), we get a palindrome (51111011115).

The spelling of 21001001103 in words is "twenty-one billion, one million, one thousand, one hundred three".