78321566400 has 672 divisors, whose sum is σ = 324101399040. Its totient is φ = 16084992000.

The previous prime is 78321566299. The next prime is 78321566419. The reversal of 78321566400 is 466512387.

It is a tau number, because it is divible by the number of its divisors (672).

It is a super-2 number, since 2×78321566400² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 32893210 + ... + 32895590.

Almost surely, 2^78321566400 is an apocalyptic number.

78321566400 is a gapful number since it is divisible by the number (70) 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 78321566400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (162050699520).

78321566400 is an abundant number, since it is smaller than the sum of its proper divisors (245779832640).

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

78321566400 is a wasteful number, since it uses less digits than its factorization.

78321566400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2513 (or 2498 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 42.

The spelling of 78321566400 in words is "seventy-eight billion, three hundred twenty-one million, five hundred sixty-six thousand, four hundred".