645053617 has 4 divisors (see below), whose sum is σ = 694673140. Its totient is φ = 595434096.

The previous prime is 645053603. The next prime is 645053639. The reversal of 645053617 is 716350546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 716350546 = 2 ⋅358175273.

It can be written as a sum of positive squares in 2 ways, for example, as 42302016 + 602751601 = 6504^2 + 24551^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645053617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645053687) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24809742 + ... + 24809767.

It is an arithmetic number, because the mean of its divisors is an integer number (173668285).

Almost surely, 2^645053617 is an apocalyptic number.

It is an amenable number.

645053617 is a deficient number, since it is larger than the sum of its proper divisors (49619523).

645053617 is a wasteful number, since it uses less digits than its factorization.

645053617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49619522.

The product of its (nonzero) digits is 75600, while the sum is 37.

The square root of 645053617 is about 25397.9057601212. The cubic root of 645053617 is about 864.0362000615.

The spelling of 645053617 in words is "six hundred forty-five million, fifty-three thousand, six hundred seventeen".