78138581400 has 864 divisors, whose sum is σ = 303790556160. Its totient is φ = 17962560000.

The previous prime is 78138581357. The next prime is 78138581401. The reversal of 78138581400 is 418583187.

It is a happy number.

It is a super-2 number, since 2×78138581400² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78138581401) by changing a digit.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 479377719 + ... + 479377881.

It is an arithmetic number, because the mean of its divisors is an integer number (351609440).

Almost surely, 2^78138581400 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78138581400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (151895278080).

78138581400 is an abundant number, since it is smaller than the sum of its proper divisors (225651974760).

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

78138581400 is a wasteful number, since it uses less digits than its factorization.

78138581400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309 (or 286 counting only the distinct ones).

The product of its (nonzero) digits is 215040, while the sum is 45.

The spelling of 78138581400 in words is "seventy-eight billion, one hundred thirty-eight million, five hundred eighty-one thousand, four hundred".