644342420456260 has 12 divisors (see below), whose sum is σ = 1353119082958188. Its totient is φ = 257736968182496.

The previous prime is 644342420456257. The next prime is 644342420456291. The reversal of 644342420456260 is 62654024243446.

It can be written as a sum of positive squares in 2 ways, for example, as 280686597719616 + 363655822736644 = 16753704^2 + 19069762^2 .

It is a super-3 number, since 3×644342420456260³ (a number of 45 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644342420456198 and 644342420456207.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16108560511387 + ... + 16108560511426.

It is an arithmetic number, because the mean of its divisors is an integer number (112759923579849).

Almost surely, 2^{644342420456260} is an apocalyptic number.

It is an amenable number.

644342420456260 is an abundant number, since it is smaller than the sum of its proper divisors (708776662501928).

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

644342420456260 is a wasteful number, since it uses less digits than its factorization.

644342420456260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32217121022822 (or 32217121022820 counting only the distinct ones).

The product of its (nonzero) digits is 26542080, while the sum is 52.

The spelling of 644342420456260 in words is "six hundred forty-four trillion, three hundred forty-two billion, four hundred twenty million, four hundred fifty-six thousand, two hundred sixty".