6405778753920 has 2688 divisors, whose sum is σ = 29385693933120. Its totient is φ = 1299619676160.

The previous prime is 6405778753903. The next prime is 6405778753939. The reversal of 6405778753920 is 293578775046.

6405778753920 is a `hidden beast` number, since 6 + 4 + 0 + 5 + 7 + 78 + 7 + 539 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (2688).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 335 ways as a sum of consecutive naturals, for example, 40801138482 + ... + 40801138638.

Almost surely, 2^{6405778753920} is an apocalyptic number.

6405778753920 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 6405778753920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14692846966560).

6405778753920 is an abundant number, since it is smaller than the sum of its proper divisors (22979915179200).

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

6405778753920 is a wasteful number, since it uses less digits than its factorization.

6405778753920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276 (or 218 counting only the distinct ones).

The product of its (nonzero) digits is 88905600, while the sum is 63.

The spelling of 6405778753920 in words is "six trillion, four hundred five billion, seven hundred seventy-eight million, seven hundred fifty-three thousand, nine hundred twenty".