645738089 has 2 divisors, whose sum is σ = 645738090. Its totient is φ = 645738088.

The previous prime is 645738083. The next prime is 645738103. The reversal of 645738089 is 980837546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 430147600 + 215590489 = 20740^2 + 14683^2 .

It is a cyclic number.

It is not a de Polignac number, because 645738089 - 2²⁸ = 377302633 is a prime.

It is a super-3 number, since 3×645738089³ (a number of 27 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (645738083) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322869044 + 322869045.

It is an arithmetic number, because the mean of its divisors is an integer number (322869045).

Almost surely, 2^645738089 is an apocalyptic number.

It is an amenable number.

645738089 is a deficient number, since it is larger than the sum of its proper divisors (1).

645738089 is an equidigital number, since it uses as much as digits as its factorization.

645738089 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1451520, while the sum is 50.

The square root of 645738089 is about 25411.3771566989. The cubic root of 645738089 is about 864.3417041367.

The spelling of 645738089 in words is "six hundred forty-five million, seven hundred thirty-eight thousand, eighty-nine".