644566046028 has 12 divisors (see below), whose sum is σ = 1503987440760. Its totient is φ = 214855348672.

The previous prime is 644566046027. The next prime is 644566046029. The reversal of 644566046028 is 820640665446.

It is an interprime number because it is at equal distance from previous prime (644566046027) and next prime (644566046029).

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (644566046023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26856918573 + ... + 26856918596.

It is an arithmetic number, because the mean of its divisors is an integer number (125332286730).

Almost surely, 2^644566046028 is an apocalyptic number.

It is an amenable number.

644566046028 is an abundant number, since it is smaller than the sum of its proper divisors (859421394732).

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

644566046028 is a wasteful number, since it uses less digits than its factorization.

644566046028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53713837176 (or 53713837174 counting only the distinct ones).

The product of its (nonzero) digits is 6635520, while the sum is 51.

The spelling of 644566046028 in words is "six hundred forty-four billion, five hundred sixty-six million, forty-six thousand, twenty-eight".