645053561 has 8 divisors (see below), whose sum is σ = 674291904. Its totient is φ = 615914640.

The previous prime is 645053551. The next prime is 645053567. The reversal of 645053561 is 165350546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645053561 - 2¹⁸ = 644791417 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (645053567) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 11426 + ... + 37691.

It is an arithmetic number, because the mean of its divisors is an integer number (84286488).

Almost surely, 2^645053561 is an apocalyptic number.

It is an amenable number.

645053561 is a deficient number, since it is larger than the sum of its proper divisors (29238343).

645053561 is a wasteful number, since it uses less digits than its factorization.

645053561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49711.

The product of its (nonzero) digits is 54000, while the sum is 35.

The square root of 645053561 is about 25397.9046576681. The cubic root of 645053561 is about 864.0361750579.

The spelling of 645053561 in words is "six hundred forty-five million, fifty-three thousand, five hundred sixty-one".