6439475698656 has 768 divisors, whose sum is σ = 23497382264832. Its totient is φ = 1490304614400.

The previous prime is 6439475698577. The next prime is 6439475698763. The reversal of 6439475698656 is 6568965749346.

It is a Harshad number since it is a multiple of its sum of digits (78).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 329695611 + ... + 329715141.

It is an arithmetic number, because the mean of its divisors is an integer number (30595549824).

Almost surely, 2^{6439475698656} is an apocalyptic number.

6439475698656 is a gapful number since it is divisible by the number (66) 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 6439475698656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11748691132416).

6439475698656 is an abundant number, since it is smaller than the sum of its proper divisors (17057906566176).

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

6439475698656 is a wasteful number, since it uses less digits than its factorization.

6439475698656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19695 (or 19687 counting only the distinct ones).

The product of its digits is 7054387200, while the sum is 78.

The spelling of 6439475698656 in words is "six trillion, four hundred thirty-nine billion, four hundred seventy-five million, six hundred ninety-eight thousand, six hundred fifty-six".