645612204605 has 4 divisors (see below), whose sum is σ = 774734645532. Its totient is φ = 516489763680.

The previous prime is 645612204569. The next prime is 645612204649. The reversal of 645612204605 is 506402216546.

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 433972642756 + 211639561849 = 658766^2 + 460043^2 .

It is not a de Polignac number, because 645612204605 - 2¹² = 645612200509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64561220456 + ... + 64561220465.

It is an arithmetic number, because the mean of its divisors is an integer number (193683661383).

Almost surely, 2^645612204605 is an apocalyptic number.

It is an amenable number.

645612204605 is a deficient number, since it is larger than the sum of its proper divisors (129122440927).

645612204605 is a wasteful number, since it uses less digits than its factorization.

645612204605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129122440926.

The product of its (nonzero) digits is 345600, while the sum is 41.

The spelling of 645612204605 in words is "six hundred forty-five billion, six hundred twelve million, two hundred four thousand, six hundred five".