644163611 has 12 divisors (see below), whose sum is σ = 797174352. Its totient is φ = 509666976.

The previous prime is 644163563. The next prime is 644163629. The reversal of 644163611 is 116361446.

It is not a de Polignac number, because 644163611 - 2²² = 639969307 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644163211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 271076 + ... + 273441.

It is an arithmetic number, because the mean of its divisors is an integer number (66431196).

Almost surely, 2^644163611 is an apocalyptic number.

644163611 is a deficient number, since it is larger than the sum of its proper divisors (153010741).

644163611 is a wasteful number, since it uses less digits than its factorization.

644163611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 544550 (or 544537 counting only the distinct ones).

The product of its digits is 10368, while the sum is 32.

The square root of 644163611 is about 25380.3784644753. The cubic root of 644163611 is about 863.6386355152.

The spelling of 644163611 in words is "six hundred forty-four million, one hundred sixty-three thousand, six hundred eleven".