645100205 has 16 divisors (see below), whose sum is σ = 808752384. Its totient is φ = 493046400.

The previous prime is 645100189. The next prime is 645100223. The reversal of 645100205 is 502001546.

It is not a de Polignac number, because 645100205 - 2⁴ = 645100189 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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, 108305 + ... + 114105.

It is an arithmetic number, because the mean of its divisors is an integer number (50547024).

Almost surely, 2^645100205 is an apocalyptic number.

It is an amenable number.

645100205 is a deficient number, since it is larger than the sum of its proper divisors (163652179).

645100205 is a wasteful number, since it uses less digits than its factorization.

645100205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6796.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 645100205 is about 25398.8229057962. The cubic root of 645100205 is about 864.0570007869.

The spelling of 645100205 in words is "six hundred forty-five million, one hundred thousand, two hundred five".