420840989 has 2 divisors, whose sum is σ = 420840990. Its totient is φ = 420840988.

The previous prime is 420840983. The next prime is 420841019. The reversal of 420840989 is 989048024.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 250747225 + 170093764 = 15835^2 + 13042^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-420840989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (420840983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210420494 + 210420495.

It is an arithmetic number, because the mean of its divisors is an integer number (210420495).

Almost surely, 2^420840989 is an apocalyptic number.

It is an amenable number.

420840989 is a deficient number, since it is larger than the sum of its proper divisors (1).

420840989 is an equidigital number, since it uses as much as digits as its factorization.

420840989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 165888, while the sum is 44.

The square root of 420840989 is about 20514.4093017567. The cubic root of 420840989 is about 749.3867514457.

The spelling of 420840989 in words is "four hundred twenty million, eight hundred forty thousand, nine hundred eighty-nine".