645704135 has 4 divisors (see below), whose sum is σ = 774844968. Its totient is φ = 516563304.

The previous prime is 645704123. The next prime is 645704161. The reversal of 645704135 is 531407546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 531407546 = 2 ⋅265703773.

It is a cyclic number.

It is not a de Polignac number, because 645704135 - 2¹⁰ = 645703111 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 645704095 and 645704104.

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, 64570409 + ... + 64570418.

It is an arithmetic number, because the mean of its divisors is an integer number (193711242).

Almost surely, 2^645704135 is an apocalyptic number.

645704135 is a deficient number, since it is larger than the sum of its proper divisors (129140833).

645704135 is a wasteful number, since it uses less digits than its factorization.

645704135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129140832.

The product of its (nonzero) digits is 50400, while the sum is 35.

The square root of 645704135 is about 25410.7090613387. The cubic root of 645704135 is about 864.3265543553.

The spelling of 645704135 in words is "six hundred forty-five million, seven hundred four thousand, one hundred thirty-five".