644216055211 has 4 divisors (see below), whose sum is σ = 678122163400. Its totient is φ = 610309947024.

The previous prime is 644216055137. The next prime is 644216055277. The reversal of 644216055211 is 112550612446.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 112550612446 = 2 ⋅56275306223.

It is a cyclic number.

It is not a de Polignac number, because 644216055211 - 2¹⁷ = 644215924139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644216055311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16953054066 + ... + 16953054103.

It is an arithmetic number, because the mean of its divisors is an integer number (169530540850).

Almost surely, 2^644216055211 is an apocalyptic number.

644216055211 is a deficient number, since it is larger than the sum of its proper divisors (33906108189).

644216055211 is a wasteful number, since it uses less digits than its factorization.

644216055211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33906108188.

The product of its (nonzero) digits is 57600, while the sum is 37.

Adding to 644216055211 its reverse (112550612446), we get a palindrome (756766667657).

The spelling of 644216055211 in words is "six hundred forty-four billion, two hundred sixteen million, fifty-five thousand, two hundred eleven".