6420989 has 2 divisors, whose sum is σ = 6420990. Its totient is φ = 6420988.

The previous prime is 6420971. The next prime is 6420991. The reversal of 6420989 is 9890246.

6420989 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6416089 + 4900 = 2533^2 + 70^2 .

It is a cyclic number.

It is not a de Polignac number, because 6420989 - 2²⁰ = 5372413 is a prime.

Together with 6420991, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6420959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3210494 + 3210495.

It is an arithmetic number, because the mean of its divisors is an integer number (3210495).

Almost surely, 2^6420989 is an apocalyptic number.

It is an amenable number.

6420989 is a deficient number, since it is larger than the sum of its proper divisors (1).

6420989 is an equidigital number, since it uses as much as digits as its factorization.

6420989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 6420989 is about 2533.9670479310. The cubic root of 6420989 is about 185.8662950149.

The spelling of 6420989 in words is "six million, four hundred twenty thousand, nine hundred eighty-nine".