21431616217 has 8 divisors (see below), whose sum is σ = 23382539712. Its totient is φ = 19481125200.

The previous prime is 21431616211. The next prime is 21431616263. The reversal of 21431616217 is 71261613412.

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 21431616217 - 2¹⁵ = 21431583449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21431616211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 228 + ... + 207034.

It is an arithmetic number, because the mean of its divisors is an integer number (2922817464).

Almost surely, 2^21431616217 is an apocalyptic number.

It is an amenable number.

21431616217 is a deficient number, since it is larger than the sum of its proper divisors (1950923495).

21431616217 is a wasteful number, since it uses less digits than its factorization.

21431616217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216239.

The product of its digits is 12096, while the sum is 34.

The spelling of 21431616217 in words is "twenty-one billion, four hundred thirty-one million, six hundred sixteen thousand, two hundred seventeen".