644102140063340 has 72 divisors (see below), whose sum is σ = 1597319688365856. Its totient is φ = 213711309100800.

The previous prime is 644102140063303. The next prime is 644102140063387. The reversal of 644102140063340 is 43360041201446.

It is a junction number, because it is equal to n+sod(n) for n = 644102140063294 and 644102140063303.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2393585321 + ... + 2393854400.

It is an arithmetic number, because the mean of its divisors is an integer number (22184995671748).

Almost surely, 2^{644102140063340} is an apocalyptic number.

It is an amenable number.

644102140063340 is an abundant number, since it is smaller than the sum of its proper divisors (953217548302516).

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

644102140063340 is a wasteful number, since it uses less digits than its factorization.

644102140063340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4787439799 (or 4787439766 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 38.

Adding to 644102140063340 its reverse (43360041201446), we get a palindrome (687462181264786).

The spelling of 644102140063340 in words is "six hundred forty-four trillion, one hundred two billion, one hundred forty million, sixty-three thousand, three hundred forty".