21020112011 has 8 divisors (see below), whose sum is σ = 21585360384. Its totient is φ = 20461109760.

The previous prime is 21020112007. The next prime is 21020112031. The reversal of 21020112011 is 11021102012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21020112011 - 2² = 21020112007 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21020111983 and 21020112001.

It is not an unprimeable number, because it can be changed into a prime (21020112031) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1554710 + ... + 1568171.

It is an arithmetic number, because the mean of its divisors is an integer number (2698170048).

Almost surely, 2^21020112011 is an apocalyptic number.

21020112011 is a deficient number, since it is larger than the sum of its proper divisors (565248373).

21020112011 is a wasteful number, since it uses less digits than its factorization.

21020112011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3123061.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21020112011 its reverse (11021102012), we get a palindrome (32041214023).

Subtracting from 21020112011 its reverse (11021102012), we obtain a palindrome (9999009999).

The spelling of 21020112011 in words is "twenty-one billion, twenty million, one hundred twelve thousand, eleven".