21133111021 has 16 divisors (see below), whose sum is σ = 23403644928. Its totient is φ = 18921372400.

The previous prime is 21133111007. The next prime is 21133111033. The reversal of 21133111021 is 12011133112.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21133111021 - 2¹⁷ = 21132979949 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21133110986 and 21133111004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21133111061) 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, 753960 + ... + 781486.

It is an arithmetic number, because the mean of its divisors is an integer number (1462727808).

Almost surely, 2^21133111021 is an apocalyptic number.

It is an amenable number.

21133111021 is a deficient number, since it is larger than the sum of its proper divisors (2270533907).

21133111021 is a wasteful number, since it uses less digits than its factorization.

21133111021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28592.

The product of its (nonzero) digits is 36, while the sum is 16.

Adding to 21133111021 its reverse (12011133112), we get a palindrome (33144244133).

The spelling of 21133111021 in words is "twenty-one billion, one hundred thirty-three million, one hundred eleven thousand, twenty-one".