21121814105 has 16 divisors (see below), whose sum is σ = 28978957440. Its totient is φ = 14477580672.

The previous prime is 21121814081. The next prime is 21121814107. The reversal of 21121814105 is 50141812112.

It is a cyclic number.

It is not a de Polignac number, because 21121814105 - 2¹⁶ = 21121748569 is a prime.

It is a super-2 number, since 2×21121814105² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21121814107) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36644 + ... + 208773.

It is an arithmetic number, because the mean of its divisors is an integer number (1811184840).

Almost surely, 2^21121814105 is an apocalyptic number.

It is an amenable number.

21121814105 is a deficient number, since it is larger than the sum of its proper divisors (7857143335).

21121814105 is a wasteful number, since it uses less digits than its factorization.

21121814105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247888.

The product of its (nonzero) digits is 640, while the sum is 26.

The spelling of 21121814105 in words is "twenty-one billion, one hundred twenty-one million, eight hundred fourteen thousand, one hundred five".