21621112011 has 12 divisors (see below), whose sum is σ = 31287596392.
Its totient is φ = 14387720256.
The previous prime is 21621112001. The next prime is 21621112039. The reversal of 21621112011 is 11021112612.
Adding to 21621112011 its reverse (11021112612), we get a palindrome (32642224623).
21621112011 is a `hidden beast` number, since 2 + 1 + 621 + 11 + 20 + 11 = 666.
It is not a de Polignac number, because 21621112011 - 215 = 21621079243 is a prime.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (21621112001) by changing a digit.
It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2191006 + ... + 2200851.
Almost surely, 221621112011 is an apocalyptic number.
21621112011 is a deficient number, since it is larger than the sum of its proper divisors (9666484381).
21621112011 is a wasteful number, since it uses less digits than its factorization.
21621112011 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 4392410 (or 4392407 counting only the distinct ones).
The product of its (nonzero) digits is 48, while the sum is 18.
The spelling of 21621112011 in words is "twenty-one billion, six hundred twenty-one million, one hundred twelve thousand, eleven".