21110111001 has 16 divisors (see below), whose sum is σ = 35741987200. Its totient is φ = 12062920464.

The previous prime is 21110110939. The next prime is 21110111003. The reversal of 21110111001 is 10011101112.

It is not a de Polignac number, because 21110111001 - 2¹⁵ = 21110078233 is a prime.

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

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21110111003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55846666 + ... + 55847043.

It is an arithmetic number, because the mean of its divisors is an integer number (2233874200).

Almost surely, 2^21110111001 is an apocalyptic number.

21110111001 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21110111001 is a deficient number, since it is larger than the sum of its proper divisors (14631876199).

21110111001 is a wasteful number, since it uses less digits than its factorization.

21110111001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111693725 (or 111693719 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 9.

Adding to 21110111001 its reverse (10011101112), we get a palindrome (31121212113).

The spelling of 21110111001 in words is "twenty-one billion, one hundred ten million, one hundred eleven thousand, one".