644406554463305 has 16 divisors (see below), whose sum is σ = 776504891623824. Its totient is φ = 513380605470720.

The previous prime is 644406554463271. The next prime is 644406554463367. The reversal of 644406554463305 is 503364455604446.

It can be written as a sum of positive squares in 8 ways, for example, as 54190092177664 + 590216462285641 = 7361392^2 + 24294371^2 .

It is not a de Polignac number, because 644406554463305 - 2²⁴ = 644406537686089 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 110915789 + ... + 116580981.

It is an arithmetic number, because the mean of its divisors is an integer number (48531555726489).

Almost surely, 2^{644406554463305} is an apocalyptic number.

It is an amenable number.

644406554463305 is a deficient number, since it is larger than the sum of its proper divisors (132098337160519).

644406554463305 is a wasteful number, since it uses less digits than its factorization.

644406554463305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5759836.

The product of its (nonzero) digits is 248832000, while the sum is 59.

The spelling of 644406554463305 in words is "six hundred forty-four trillion, four hundred six billion, five hundred fifty-four million, four hundred sixty-three thousand, three hundred five".