645399607 has 2 divisors, whose sum is σ = 645399608. Its totient is φ = 645399606.

The previous prime is 645399593. The next prime is 645399647. The reversal of 645399607 is 706993546.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645399607 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645399647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322699803 + 322699804.

It is an arithmetic number, because the mean of its divisors is an integer number (322699804).

Almost surely, 2^645399607 is an apocalyptic number.

645399607 is a deficient number, since it is larger than the sum of its proper divisors (1).

645399607 is an equidigital number, since it uses as much as digits as its factorization.

645399607 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1224720, while the sum is 49.

The square root of 645399607 is about 25404.7162353765. The cubic root of 645399607 is about 864.1906546389.

It can be divided in two parts, 645399 and 607, that multiplied together give a palindrome (391757193).

The spelling of 645399607 in words is "six hundred forty-five million, three hundred ninety-nine thousand, six hundred seven".