21003311121 has 16 divisors (see below), whose sum is σ = 30894178560. Its totient is φ = 12609866880.

The previous prime is 21003311111. The next prime is 21003311129. The reversal of 21003311121 is 12111330012.

It is a happy number.

It is not a de Polignac number, because 21003311121 - 2¹⁵ = 21003278353 is a prime.

It is a super-2 number, since 2×21003311121² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21003311121.

It is not an unprimeable number, because it can be changed into a prime (21003311129) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6566041 + ... + 6569238.

It is an arithmetic number, because the mean of its divisors is an integer number (1930886160).

Almost surely, 2^21003311121 is an apocalyptic number.

It is an amenable number.

21003311121 is a deficient number, since it is larger than the sum of its proper divisors (9890867439).

21003311121 is a wasteful number, since it uses less digits than its factorization.

21003311121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13135336.

The product of its (nonzero) digits is 36, while the sum is 15.

Adding to 21003311121 its reverse (12111330012), we get a palindrome (33114641133).

The spelling of 21003311121 in words is "twenty-one billion, three million, three hundred eleven thousand, one hundred twenty-one".