645540136125208 has 16 divisors (see below), whose sum is σ = 1210430013380280. Its totient is φ = 322758799223808.

The previous prime is 645540136125121. The next prime is 645540136125233. The reversal of 645540136125208 is 802521631045546.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1408361385 + ... + 1408819672.

Almost surely, 2^{645540136125208} is an apocalyptic number.

It is an amenable number.

645540136125208 is a deficient number, since it is larger than the sum of its proper divisors (564889877255072).

645540136125208 is a wasteful number, since it uses less digits than its factorization.

645540136125208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2817209706 (or 2817209702 counting only the distinct ones).

The product of its (nonzero) digits is 6912000, while the sum is 52.

The spelling of 645540136125208 in words is "six hundred forty-five trillion, five hundred forty billion, one hundred thirty-six million, one hundred twenty-five thousand, two hundred eight".