645608135 has 4 divisors (see below), whose sum is σ = 774729768. Its totient is φ = 516486504.

The previous prime is 645608123. The next prime is 645608143. The reversal of 645608135 is 531806546.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 645608135 - 2¹⁸ = 645345991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 64560809 + ... + 64560818.

It is an arithmetic number, because the mean of its divisors is an integer number (193682442).

Almost surely, 2^645608135 is an apocalyptic number.

645608135 is a deficient number, since it is larger than the sum of its proper divisors (129121633).

645608135 is a wasteful number, since it uses less digits than its factorization.

645608135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129121632.

The product of its (nonzero) digits is 86400, while the sum is 38.

The square root of 645608135 is about 25408.8200237634. The cubic root of 645608135 is about 864.2837176767.

The spelling of 645608135 in words is "six hundred forty-five million, six hundred eight thousand, one hundred thirty-five".