194778517878 has 96 divisors (see below), whose sum is σ = 496557734400. Its totient is φ = 54020545920.

The previous prime is 194778517867. The next prime is 194778517933. The reversal of 194778517878 is 878715877491.

194778517878 is a `hidden beast` number, since 1 + 9 + 477 + 85 + 1 + 7 + 8 + 78 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 933301 + ... + 1122767.

It is an arithmetic number, because the mean of its divisors is an integer number (5172476400).

Almost surely, 2^194778517878 is an apocalyptic number.

194778517878 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 194778517878, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (248278867200).

194778517878 is an abundant number, since it is smaller than the sum of its proper divisors (301779216522).

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

194778517878 is a wasteful number, since it uses less digits than its factorization.

194778517878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189722 (or 189719 counting only the distinct ones).

The product of its digits is 221276160, while the sum is 72.

The spelling of 194778517878 in words is "one hundred ninety-four billion, seven hundred seventy-eight million, five hundred seventeen thousand, eight hundred seventy-eight".