645321203049601 has 4 divisors (see below), whose sum is σ = 694961295591892. Its totient is φ = 595681110507312.

The previous prime is 645321203049599. The next prime is 645321203049647. The reversal of 645321203049601 is 106940302123546.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 205755385118976 + 439565817930625 = 14344176^2 + 20965825^2 .

It is a cyclic number.

It is not a de Polignac number, because 645321203049601 - 2¹ = 645321203049599 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645321203349601) 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, 24820046271126 + ... + 24820046271151.

It is an arithmetic number, because the mean of its divisors is an integer number (173740323897973).

Almost surely, 2^{645321203049601} is an apocalyptic number.

It is an amenable number.

645321203049601 is a deficient number, since it is larger than the sum of its proper divisors (49640092542291).

645321203049601 is a wasteful number, since it uses less digits than its factorization.

645321203049601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49640092542290.

The product of its (nonzero) digits is 933120, while the sum is 46.

The spelling of 645321203049601 in words is "six hundred forty-five trillion, three hundred twenty-one billion, two hundred three million, forty-nine thousand, six hundred one".