11005208021 has 4 divisors (see below), whose sum is σ = 11005760844. Its totient is φ = 11004655200.

The previous prime is 11005207943. The next prime is 11005208087. The reversal of 11005208021 is 12080250011.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12080250011 = 21871 ⋅552341.

It can be written as a sum of positive squares in 2 ways, for example, as 1022400625 + 9982807396 = 31975^2 + 99914^2 .

It is a cyclic number.

It is not a de Polignac number, because 11005208021 - 2¹⁰ = 11005206997 is a prime.

It is a super-2 number, since 2×11005208021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11005207984 and 11005208002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11005208321) 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, 245390 + ... + 286751.

It is an arithmetic number, because the mean of its divisors is an integer number (2751440211).

Almost surely, 2^11005208021 is an apocalyptic number.

It is an amenable number.

11005208021 is a deficient number, since it is larger than the sum of its proper divisors (552823).

11005208021 is an equidigital number, since it uses as much as digits as its factorization.

11005208021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 552822.

The product of its (nonzero) digits is 160, while the sum is 20.

Adding to 11005208021 its reverse (12080250011), we get a palindrome (23085458032).

The spelling of 11005208021 in words is "eleven billion, five million, two hundred eight thousand, twenty-one".