77961636648 has 256 divisors, whose sum is σ = 262642176000. Its totient is φ = 20944611072.

The previous prime is 77961636619. The next prime is 77961636673. The reversal of 77961636648 is 84663616977.

77961636648 is a `hidden beast` number, since 7 + 7 + 9 + 616 + 3 + 6 + 6 + 4 + 8 = 666.

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

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2032786 + ... + 2070782.

It is an arithmetic number, because the mean of its divisors is an integer number (1025946000).

Almost surely, 2^77961636648 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 77961636648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131321088000).

77961636648 is an abundant number, since it is smaller than the sum of its proper divisors (184680539352).

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

77961636648 is a wasteful number, since it uses less digits than its factorization.

77961636648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38101 (or 38091 counting only the distinct ones).

The product of its digits is 54867456, while the sum is 63.

The spelling of 77961636648 in words is "seventy-seven billion, nine hundred sixty-one million, six hundred thirty-six thousand, six hundred forty-eight".