644225255 has 4 divisors (see below), whose sum is σ = 773070312. Its totient is φ = 515380200.

The previous prime is 644225249. The next prime is 644225261. The reversal of 644225255 is 552522446.

644225255 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 is an interprime number because it is at equal distance from previous prime (644225249) and next prime (644225261).

It is a de Polignac number, because none of the positive numbers 2^k-644225255 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, 64422521 + ... + 64422530.

It is an arithmetic number, because the mean of its divisors is an integer number (193267578).

Almost surely, 2^644225255 is an apocalyptic number.

644225255 is a deficient number, since it is larger than the sum of its proper divisors (128845057).

644225255 is a wasteful number, since it uses less digits than its factorization.

644225255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128845056.

The product of its digits is 96000, while the sum is 35.

The square root of 644225255 is about 25381.5928381179. The cubic root of 644225255 is about 863.6661836107. Note that the first 3 decimals are identical.

The spelling of 644225255 in words is "six hundred forty-four million, two hundred twenty-five thousand, two hundred fifty-five".