21989897117 has 4 divisors (see below), whose sum is σ = 22006570080. Its totient is φ = 21973224156.

The previous prime is 21989897113. The next prime is 21989897119. The reversal of 21989897117 is 71179898912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21989897117 - 2² = 21989897113 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21989897117.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21989897113) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8334503 + ... + 8337140.

It is an arithmetic number, because the mean of its divisors is an integer number (5501642520).

Almost surely, 2^21989897117 is an apocalyptic number.

It is an amenable number.

21989897117 is a deficient number, since it is larger than the sum of its proper divisors (16672963).

21989897117 is a wasteful number, since it uses less digits than its factorization.

21989897117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16672962.

The product of its digits is 4572288, while the sum is 62.

The spelling of 21989897117 in words is "twenty-one billion, nine hundred eighty-nine million, eight hundred ninety-seven thousand, one hundred seventeen".