77478416640 has 216 divisors, whose sum is σ = 283836630168. Its totient is φ = 19445514240.

The previous prime is 77478416633. The next prime is 77478416641. The reversal of 77478416640 is 4661487477.

77478416640 is a `hidden beast` number, since 7 + 7 + 478 + 4 + 166 + 4 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 8591065344 + 68887351296 = 92688^2 + 262464^2 .

It is a super-3 number, since 3×77478416640³ (a number of 34 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (77478416641) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1971 + ... + 393650.

It is an arithmetic number, because the mean of its divisors is an integer number (1314058473).

Almost surely, 2^77478416640 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 77478416640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141918315084).

77478416640 is an abundant number, since it is smaller than the sum of its proper divisors (206358213528).

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

77478416640 is a wasteful number, since it uses less digits than its factorization.

77478416640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 395665 (or 395648 counting only the distinct ones).

The product of its (nonzero) digits is 6322176, while the sum is 54.

The spelling of 77478416640 in words is "seventy-seven billion, four hundred seventy-eight million, four hundred sixteen thousand, six hundred forty".