21606005106 has 24 divisors (see below), whose sum is σ = 53500584384. Its totient is φ = 6173144280.

The previous prime is 21606005089. The next prime is 21606005131. The reversal of 21606005106 is 60150060612.

It is a happy number.

21606005106 is a `hidden beast` number, since 2 + 1 + 6 + 0 + 600 + 51 + 0 + 6 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21606005106.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 85737990 + ... + 85738241.

It is an arithmetic number, because the mean of its divisors is an integer number (2229191016).

Almost surely, 2^21606005106 is an apocalyptic number.

21606005106 is an abundant number, since it is smaller than the sum of its proper divisors (31894579278).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21606005106 is a wasteful number, since it uses less digits than its factorization.

21606005106 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171476246 (or 171476243 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

Adding to 21606005106 its reverse (60150060612), we get a palindrome (81756065718).

The spelling of 21606005106 in words is "twenty-one billion, six hundred six million, five thousand, one hundred six".