645906515389 has 2 divisors, whose sum is σ = 645906515390. Its totient is φ = 645906515388.

The previous prime is 645906515279. The next prime is 645906515393. The reversal of 645906515389 is 983515609546.

645906515389 is digitally balanced in base 2, 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., 372307428900 + 273599086489 = 610170^2 + 523067^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645906515389 is a prime.

It is a super-3 number, since 3×645906515389³ (a number of 36 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645906515689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322953257694 + 322953257695.

It is an arithmetic number, because the mean of its divisors is an integer number (322953257695).

Almost surely, 2^645906515389 is an apocalyptic number.

It is an amenable number.

645906515389 is a deficient number, since it is larger than the sum of its proper divisors (1).

645906515389 is an equidigital number, since it uses as much as digits as its factorization.

645906515389 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992000, while the sum is 61.

The spelling of 645906515389 in words is "six hundred forty-five billion, nine hundred six million, five hundred fifteen thousand, three hundred eighty-nine".