645561200255545 has 16 divisors (see below), whose sum is σ = 885504814691328. Its totient is φ = 442588667290560.

The previous prime is 645561200255539. The next prime is 645561200255557. The reversal of 645561200255545 is 545552002165546.

It is a happy number.

It is not a de Polignac number, because 645561200255545 - 2³⁹ = 645011444441657 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1705433626 + ... + 1705812115.

It is an arithmetic number, because the mean of its divisors is an integer number (55344050918208).

Almost surely, 2^{645561200255545} is an apocalyptic number.

It is an amenable number.

645561200255545 is a deficient number, since it is larger than the sum of its proper divisors (239943614435783).

645561200255545 is a wasteful number, since it uses less digits than its factorization.

645561200255545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3411251160.

The product of its (nonzero) digits is 36000000, while the sum is 55.

The spelling of 645561200255545 in words is "six hundred forty-five trillion, five hundred sixty-one billion, two hundred million, two hundred fifty-five thousand, five hundred forty-five".