644232773220 has 48 divisors (see below), whose sum is σ = 1815341293248. Its totient is φ = 170701165440.

The previous prime is 644232773213. The next prime is 644232773221. The reversal of 644232773220 is 22377232446.

It is not an unprimeable number, because it can be changed into a prime (644232773221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34185526 + ... + 34204365.

It is an arithmetic number, because the mean of its divisors is an integer number (37819610276).

Almost surely, 2^644232773220 is an apocalyptic number.

644232773220 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

644232773220 is an abundant number, since it is smaller than the sum of its proper divisors (1171108520028).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644232773220 is a wasteful number, since it uses less digits than its factorization.

644232773220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68390060 (or 68390058 counting only the distinct ones).

The product of its (nonzero) digits is 677376, while the sum is 42.

The spelling of 644232773220 in words is "six hundred forty-four billion, two hundred thirty-two million, seven hundred seventy-three thousand, two hundred twenty".