78399440000 has 160 divisors (see below), whose sum is σ = 223053600000. Its totient is φ = 26879616000.

The previous prime is 78399439991. The next prime is 78399440003. The reversal of 78399440000 is 4499387.

It is a Cunningham number, because it is equal to 279999²-1.

It is a tau number, because it is divible by the number of its divisors (160).

It is a super-2 number, since 2×78399440000² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78399440003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 490001 + ... + 629999.

It is an arithmetic number, because the mean of its divisors is an integer number (1394085000).

Almost surely, 2^78399440000 is an apocalyptic number.

78399440000 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 78399440000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111526800000).

78399440000 is an abundant number, since it is smaller than the sum of its proper divisors (144654160000).

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

78399440000 is an equidigital number, since it uses as much as digits as its factorization.

78399440000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140040 (or 140013 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 44.

The spelling of 78399440000 in words is "seventy-eight billion, three hundred ninety-nine million, four hundred forty thousand".