21428338417 has 2 divisors, whose sum is σ = 21428338418. Its totient is φ = 21428338416.

The previous prime is 21428338319. The next prime is 21428338427. The reversal of 21428338417 is 71483382412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16230505201 + 5197833216 = 127399^2 + 72096^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21428338417 is a prime.

It is not a weakly prime, because it can be changed into another prime (21428338427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10714169208 + 10714169209.

It is an arithmetic number, because the mean of its divisors is an integer number (10714169209).

Almost surely, 2^21428338417 is an apocalyptic number.

It is an amenable number.

21428338417 is a deficient number, since it is larger than the sum of its proper divisors (1).

21428338417 is an equidigital number, since it uses as much as digits as its factorization.

21428338417 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 258048, while the sum is 43.

The spelling of 21428338417 in words is "twenty-one billion, four hundred twenty-eight million, three hundred thirty-eight thousand, four hundred seventeen".