21105106217 has 8 divisors (see below), whose sum is σ = 22750465920. Its totient is φ = 19462873680.

The previous prime is 21105106171. The next prime is 21105106219. The reversal of 21105106217 is 71260150112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21105106217 - 2¹⁰ = 21105105193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21105106219) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 767759 + ... + 794772.

It is an arithmetic number, because the mean of its divisors is an integer number (2843808240).

Almost surely, 2^21105106217 is an apocalyptic number.

It is an amenable number.

21105106217 is a deficient number, since it is larger than the sum of its proper divisors (1645359703).

21105106217 is a wasteful number, since it uses less digits than its factorization.

21105106217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1563583.

The product of its (nonzero) digits is 840, while the sum is 26.

Adding to 21105106217 its reverse (71260150112), we get a palindrome (92365256329).

The spelling of 21105106217 in words is "twenty-one billion, one hundred five million, one hundred six thousand, two hundred seventeen".