21606346417 has 2 divisors, whose sum is σ = 21606346418. Its totient is φ = 21606346416.

The previous prime is 21606346387. The next prime is 21606346457. The reversal of 21606346417 is 71464360612.

It is an a-pointer prime, because the next prime (21606346457) can be obtained adding 21606346417 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19188067441 + 2418278976 = 138521^2 + 49176^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21606346417 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21606346417.

It is not a weakly prime, because it can be changed into another prime (21606346457) 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 as a sum of consecutive naturals, namely, 10803173208 + 10803173209.

It is an arithmetic number, because the mean of its divisors is an integer number (10803173209).

Almost surely, 2^21606346417 is an apocalyptic number.

It is an amenable number.

21606346417 is a deficient number, since it is larger than the sum of its proper divisors (1).

21606346417 is an equidigital number, since it uses as much as digits as its factorization.

21606346417 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 145152, while the sum is 40.

The spelling of 21606346417 in words is "twenty-one billion, six hundred six million, three hundred forty-six thousand, four hundred seventeen".