645552205 has 4 divisors (see below), whose sum is σ = 774662652. Its totient is φ = 516441760.

The previous prime is 645552197. The next prime is 645552211. The reversal of 645552205 is 502255546.

645552205 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 171793449 + 473758756 = 13107^2 + 21766^2 .

It is not a de Polignac number, because 645552205 - 2³ = 645552197 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, 64555216 + ... + 64555225.

It is an arithmetic number, because the mean of its divisors is an integer number (193665663).

Almost surely, 2^645552205 is an apocalyptic number.

It is an amenable number.

645552205 is a deficient number, since it is larger than the sum of its proper divisors (129110447).

645552205 is a wasteful number, since it uses less digits than its factorization.

645552205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129110446.

The product of its (nonzero) digits is 60000, while the sum is 34.

The square root of 645552205 is about 25407.7193978523. The cubic root of 645552205 is about 864.2587588915.

The spelling of 645552205 in words is "six hundred forty-five million, five hundred fifty-two thousand, two hundred five".