639216805500 has 960 divisors, whose sum is σ = 2580671149056. Its totient is φ = 134136000000.

The previous prime is 639216805453. The next prime is 639216805517. The reversal of 639216805500 is 5508612936.

639216805500 is a `hidden beast` number, since 6 + 3 + 9 + 2 + 16 + 80 + 550 + 0 = 666.

It is a super-3 number, since 3×639216805500³ (a number of 36 digits) contains 333 as substring.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

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 319 ways as a sum of consecutive naturals, for example, 925060155 + ... + 925060845.

Almost surely, 2^639216805500 is an apocalyptic number.

639216805500 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 639216805500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1290335574528).

639216805500 is an abundant number, since it is smaller than the sum of its proper divisors (1941454343556).

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

639216805500 is a wasteful number, since it uses less digits than its factorization.

639216805500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 993 (or 972 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 45.

The spelling of 639216805500 in words is "six hundred thirty-nine billion, two hundred sixteen million, eight hundred five thousand, five hundred".