21001112116 has 6 divisors (see below), whose sum is σ = 36751946210. Its totient is φ = 10500556056.

The previous prime is 21001112071. The next prime is 21001112117. The reversal of 21001112116 is 61121110012.

It can be written as a sum of positive squares in only one way, i.e., 11001912100 + 9999200016 = 104890^2 + 99996^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21001112116.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001112117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2625139011 + ... + 2625139018.

Almost surely, 2^21001112116 is an apocalyptic number.

It is an amenable number.

21001112116 is a deficient number, since it is larger than the sum of its proper divisors (15750834094).

21001112116 is a wasteful number, since it uses less digits than its factorization.

21001112116 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5250278033 (or 5250278031 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 16.

Adding to 21001112116 its reverse (61121110012), we get a palindrome (82122222128).

The spelling of 21001112116 in words is "twenty-one billion, one million, one hundred twelve thousand, one hundred sixteen".