646252889 has 2 divisors, whose sum is σ = 646252890. Its totient is φ = 646252888.

The previous prime is 646252861. The next prime is 646252927. The reversal of 646252889 is 988252646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 424689664 + 221563225 = 20608^2 + 14885^2 .

It is a cyclic number.

It is not a de Polignac number, because 646252889 - 2²⁴ = 629475673 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (646252489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323126444 + 323126445.

It is an arithmetic number, because the mean of its divisors is an integer number (323126445).

Almost surely, 2^646252889 is an apocalyptic number.

It is an amenable number.

646252889 is a deficient number, since it is larger than the sum of its proper divisors (1).

646252889 is an equidigital number, since it uses as much as digits as its factorization.

646252889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1658880, while the sum is 50.

The square root of 646252889 is about 25421.5044598073. The cubic root of 646252889 is about 864.5713353776.

The spelling of 646252889 in words is "six hundred forty-six million, two hundred fifty-two thousand, eight hundred eighty-nine".