21418417717 has 12 divisors (see below), whose sum is σ = 23031564300. Its totient is φ = 19908263232.

The previous prime is 21418417667. The next prime is 21418417747. The reversal of 21418417717 is 71771481412.

It can be written as a sum of positive squares in 2 ways, for example, as 8547742116 + 12870675601 = 92454^2 + 113449^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21418417717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21418417747) 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 11 ways as a sum of consecutive naturals, for example, 540592 + ... + 578857.

It is an arithmetic number, because the mean of its divisors is an integer number (1919297025).

Almost surely, 2^21418417717 is an apocalyptic number.

It is an amenable number.

21418417717 is a deficient number, since it is larger than the sum of its proper divisors (1613146583).

21418417717 is a wasteful number, since it uses less digits than its factorization.

21418417717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1119540 (or 1119521 counting only the distinct ones).

The product of its digits is 87808, while the sum is 43.

The spelling of 21418417717 in words is "twenty-one billion, four hundred eighteen million, four hundred seventeen thousand, seven hundred seventeen".