78394477770 has 192 divisors, whose sum is σ = 242862706944. Its totient is φ = 17171481600.

The previous prime is 78394477757. The next prime is 78394477771. The reversal of 78394477770 is 7777449387.

78394477770 is a `hidden beast` number, since 7 + 8 + 3 + 94 + 477 + 7 + 70 = 666.

It is a super-2 number, since 2×78394477770² (a number of 23 digits) contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 78394477698 and 78394477707.

It is not an unprimeable number, because it can be changed into a prime (78394477771) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1408470 + ... + 1463070.

It is an arithmetic number, because the mean of its divisors is an integer number (1264909932).

Almost surely, 2^78394477770 is an apocalyptic number.

78394477770 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 78394477770, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121431353472).

78394477770 is an abundant number, since it is smaller than the sum of its proper divisors (164468229174).

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

78394477770 is a wasteful number, since it uses less digits than its factorization.

78394477770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54717 (or 54714 counting only the distinct ones).

The product of its (nonzero) digits is 58084992, while the sum is 63.

The spelling of 78394477770 in words is "seventy-eight billion, three hundred ninety-four million, four hundred seventy-seven thousand, seven hundred seventy".