639434686665600 has 768 divisors, whose sum is σ = 2686243294425600. Its totient is φ = 145512607334400.

The previous prime is 639434686665557. The next prime is 639434686665637. The reversal of 639434686665600 is 6566686434936.

639434686665600 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×639434686665600² (a number of 30 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 134960820 + ... + 139618380.

It is an arithmetic number, because the mean of its divisors is an integer number (3497712622950).

Almost surely, 2^{639434686665600} is an apocalyptic number.

639434686665600 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639434686665600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1343121647212800).

639434686665600 is an abundant number, since it is smaller than the sum of its proper divisors (2046808607760000).

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

639434686665600 is a wasteful number, since it uses less digits than its factorization.

639434686665600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4657828 (or 4657805 counting only the distinct ones).

The product of its (nonzero) digits is 2418647040, while the sum is 72.

The spelling of 639434686665600 in words is "six hundred thirty-nine trillion, four hundred thirty-four billion, six hundred eighty-six million, six hundred sixty-five thousand, six hundred".