21002240011 has 4 divisors (see below), whose sum is σ = 22237665912. Its totient is φ = 19766814112.

The previous prime is 21002239961. The next prime is 21002240047. The reversal of 21002240011 is 11004220012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21002240011 - 2⁷ = 21002239883 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002239973 and 21002240000.

It is not an unprimeable number, because it can be changed into a prime (21002241011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 617712925 + ... + 617712958.

It is an arithmetic number, because the mean of its divisors is an integer number (5559416478).

Almost surely, 2^21002240011 is an apocalyptic number.

21002240011 is a deficient number, since it is larger than the sum of its proper divisors (1235425901).

21002240011 is a wasteful number, since it uses less digits than its factorization.

21002240011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1235425900.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21002240011 its reverse (11004220012), we get a palindrome (32006460023).

The spelling of 21002240011 in words is "twenty-one billion, two million, two hundred forty thousand, eleven".