428217865921 has 2 divisors, whose sum is σ = 428217865922. Its totient is φ = 428217865920.

The previous prime is 428217865891. The next prime is 428217865963. The reversal of 428217865921 is 129568712824.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 404446393521 + 23771472400 = 635961^2 + 154180^2 .

It is a cyclic number.

It is not a de Polignac number, because 428217865921 - 2⁹ = 428217865409 is a prime.

It is a super-3 number, since 3×428217865921³ (a number of 36 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (428217835921) 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, 214108932960 + 214108932961.

It is an arithmetic number, because the mean of its divisors is an integer number (214108932961).

Almost surely, 2^428217865921 is an apocalyptic number.

It is an amenable number.

428217865921 is a deficient number, since it is larger than the sum of its proper divisors (1).

428217865921 is an equidigital number, since it uses as much as digits as its factorization.

428217865921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3870720, while the sum is 55.

The spelling of 428217865921 in words is "four hundred twenty-eight billion, two hundred seventeen million, eight hundred sixty-five thousand, nine hundred twenty-one".