645747545 has 4 divisors (see below), whose sum is σ = 774897060. Its totient is φ = 516598032.

The previous prime is 645747521. The next prime is 645747559. The reversal of 645747545 is 545747546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 545747546 = 2 ⋅272873773.

It can be written as a sum of positive squares in 2 ways, for example, as 335036416 + 310711129 = 18304^2 + 17627^2 .

It is a cyclic number.

It is not a de Polignac number, because 645747545 - 2⁶ = 645747481 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645747545.

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, 64574750 + ... + 64574759.

It is an arithmetic number, because the mean of its divisors is an integer number (193724265).

Almost surely, 2^645747545 is an apocalyptic number.

It is an amenable number.

645747545 is a deficient number, since it is larger than the sum of its proper divisors (129149515).

645747545 is a wasteful number, since it uses less digits than its factorization.

645747545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129149514.

The product of its digits is 2352000, while the sum is 47.

The square root of 645747545 is about 25411.5632144109. The cubic root of 645747545 is about 864.3459231720.

Subtracting from 645747545 its reverse (545747546), we obtain a palindrome (99999999).

The spelling of 645747545 in words is "six hundred forty-five million, seven hundred forty-seven thousand, five hundred forty-five".