421220639789 has 2 divisors, whose sum is σ = 421220639790. Its totient is φ = 421220639788.

The previous prime is 421220639767. The next prime is 421220639869. The reversal of 421220639789 is 987936022124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 405628872100 + 15591767689 = 636890^2 + 124867^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-421220639789 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 421220639789.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (421220639759) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210610319894 + 210610319895.

It is an arithmetic number, because the mean of its divisors is an integer number (210610319895).

Almost surely, 2^421220639789 is an apocalyptic number.

It is an amenable number.

421220639789 is a deficient number, since it is larger than the sum of its proper divisors (1).

421220639789 is an equidigital number, since it uses as much as digits as its factorization.

421220639789 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2612736, while the sum is 53.

The spelling of 421220639789 in words is "four hundred twenty-one billion, two hundred twenty million, six hundred thirty-nine thousand, seven hundred eighty-nine".