21214445617 has 8 divisors (see below), whose sum is σ = 21646139112. Its totient is φ = 20785459200.

The previous prime is 21214445587. The next prime is 21214445621. The reversal of 21214445617 is 71654441212.

It can be written as a sum of positive squares in 4 ways, for example, as 5265534096 + 15948911521 = 72564^2 + 126289^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21214445617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21214445647) 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, 660934 + ... + 692287.

It is an arithmetic number, because the mean of its divisors is an integer number (2705767389).

Almost surely, 2^21214445617 is an apocalyptic number.

It is an amenable number.

21214445617 is a deficient number, since it is larger than the sum of its proper divisors (431693495).

21214445617 is a wasteful number, since it uses less digits than its factorization.

21214445617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1353539.

The product of its digits is 53760, while the sum is 37.

Adding to 21214445617 its reverse (71654441212), we get a palindrome (92868886829).

The spelling of 21214445617 in words is "twenty-one billion, two hundred fourteen million, four hundred forty-five thousand, six hundred seventeen".