646622789 has 2 divisors, whose sum is σ = 646622790. Its totient is φ = 646622788.

The previous prime is 646622749. The next prime is 646622791. The reversal of 646622789 is 987226646.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 493284100 + 153338689 = 22210^2 + 12383^2 .

It is a cyclic number.

It is not a de Polignac number, because 646622789 - 2¹⁶ = 646557253 is a prime.

Together with 646622791, 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 (646622719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323311394 + 323311395.

It is an arithmetic number, because the mean of its divisors is an integer number (323311395).

Almost surely, 2^646622789 is an apocalyptic number.

It is an amenable number.

646622789 is a deficient number, since it is larger than the sum of its proper divisors (1).

646622789 is an equidigital number, since it uses as much as digits as its factorization.

646622789 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1741824, while the sum is 50.

The square root of 646622789 is about 25428.7787555753. The cubic root of 646622789 is about 864.7362573690.

The spelling of 646622789 in words is "six hundred forty-six million, six hundred twenty-two thousand, seven hundred eighty-nine".