645664355265 has 16 divisors (see below), whose sum is σ = 1033101292608. Its totient is φ = 344341548096.

The previous prime is 645664355257. The next prime is 645664355267. The reversal of 645664355265 is 562553466546.

It is not a de Polignac number, because 645664355265 - 2³ = 645664355257 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645664355267) 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 15 ways as a sum of consecutive naturals, for example, 373302 + ... + 1196111.

It is an arithmetic number, because the mean of its divisors is an integer number (64568830788).

Almost surely, 2^645664355265 is an apocalyptic number.

It is an amenable number.

645664355265 is a deficient number, since it is larger than the sum of its proper divisors (387436937343).

645664355265 is a wasteful number, since it uses less digits than its factorization.

645664355265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1596848.

The product of its digits is 77760000, while the sum is 57.

The spelling of 645664355265 in words is "six hundred forty-five billion, six hundred sixty-four million, three hundred fifty-five thousand, two hundred sixty-five".