645135969599 has 16 divisors (see below), whose sum is σ = 726549626880. Its totient is φ = 567519708000.

The previous prime is 645135969559. The next prime is 645135969601. The reversal of 645135969599 is 995969531546.

It is a cyclic number.

It is not a de Polignac number, because 645135969599 - 2⁸ = 645135969343 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645135969539) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4246157 + ... + 4395465.

It is an arithmetic number, because the mean of its divisors is an integer number (45409351680).

Almost surely, 2^645135969599 is an apocalyptic number.

645135969599 is a deficient number, since it is larger than the sum of its proper divisors (81413657281).

645135969599 is a wasteful number, since it uses less digits than its factorization.

645135969599 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162022.

The product of its digits is 354294000, while the sum is 71.

The spelling of 645135969599 in words is "six hundred forty-five billion, one hundred thirty-five million, nine hundred sixty-nine thousand, five hundred ninety-nine".