642950989 has 2 divisors, whose sum is σ = 642950990. Its totient is φ = 642950988.

The previous prime is 642950981. The next prime is 642951011. The reversal of 642950989 is 989059246.

642950989 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 451350025 + 191600964 = 21245^2 + 13842^2 .

It is a cyclic number.

It is not a de Polignac number, because 642950989 - 2³ = 642950981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642950981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321475494 + 321475495.

It is an arithmetic number, because the mean of its divisors is an integer number (321475495).

Almost surely, 2^642950989 is an apocalyptic number.

It is an amenable number.

642950989 is a deficient number, since it is larger than the sum of its proper divisors (1).

642950989 is an equidigital number, since it uses as much as digits as its factorization.

642950989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1399680, while the sum is 52.

The square root of 642950989 is about 25356.4782452138. The cubic root of 642950989 is about 863.0963690107.

The spelling of 642950989 in words is "six hundred forty-two million, nine hundred fifty thousand, nine hundred eighty-nine".