77553785664 has 280 divisors, whose sum is σ = 245855157768. Its totient is φ = 24086937600.

The previous prime is 77553785599. The next prime is 77553785669. The reversal of 77553785664 is 46658735577.

It is a happy number.

77553785664 is a `hidden beast` number, since 7 + 7 + 553 + 78 + 5 + 6 + 6 + 4 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 64049486400 + 13504299264 = 253080^2 + 116208^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77553785669) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 8896572 + ... + 8905284.

Almost surely, 2^77553785664 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 77553785664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122927578884).

77553785664 is an abundant number, since it is smaller than the sum of its proper divisors (168301372104).

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

77553785664 is a wasteful number, since it uses less digits than its factorization.

77553785664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8855 (or 8836 counting only the distinct ones).

The product of its digits is 148176000, while the sum is 63.

The spelling of 77553785664 in words is "seventy-seven billion, five hundred fifty-three million, seven hundred eighty-five thousand, six hundred sixty-four".