644238273696 has 48 divisors (see below), whose sum is σ = 1711500495264. Its totient is φ = 212158786304.

The previous prime is 644238273691. The next prime is 644238273733. The reversal of 644238273696 is 696372832446.

It is a tau number, because it is divible by the number of its divisors (48).

It is not an unprimeable number, because it can be changed into a prime (644238273691) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40418631 + ... + 40434566.

It is an arithmetic number, because the mean of its divisors is an integer number (35656260318).

Almost surely, 2^644238273696 is an apocalyptic number.

It is an amenable number.

644238273696 is an abundant number, since it is smaller than the sum of its proper divisors (1067262221568).

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

644238273696 is a wasteful number, since it uses less digits than its factorization.

644238273696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80853293 (or 80853285 counting only the distinct ones).

The product of its digits is 62705664, while the sum is 60.

The spelling of 644238273696 in words is "six hundred forty-four billion, two hundred thirty-eight million, two hundred seventy-three thousand, six hundred ninety-six".