6643853798400 has 2640 divisors, whose sum is σ = 30618345675456. Its totient is φ = 1386133585920.

The previous prime is 6643853798363. The next prime is 6643853798489. The reversal of 6643853798400 is 48973583466.

6643853798400 is a `hidden beast` number, since 6 + 6 + 4 + 3 + 8 + 537 + 98 + 4 + 0 + 0 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 25851571072 + ... + 25851571328.

Almost surely, 2^{6643853798400} is an apocalyptic number.

6643853798400 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 6643853798400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15309172837728).

6643853798400 is an abundant number, since it is smaller than the sum of its proper divisors (23974491877056).

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

6643853798400 is a wasteful number, since it uses less digits than its factorization.

6643853798400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456 (or 424 counting only the distinct ones).

The product of its (nonzero) digits is 104509440, while the sum is 63.

The spelling of 6643853798400 in words is "six trillion, six hundred forty-three billion, eight hundred fifty-three million, seven hundred ninety-eight thousand, four hundred".