77861988851556 has 432 divisors, whose sum is σ = 242903305673280. Its totient is φ = 19279661506560.

The previous prime is 77861988851551. The next prime is 77861988851653. The reversal of 77861988851556 is 65515888916877.

77861988851556 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×77861988851556² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (84).

It is not an unprimeable number, because it can be changed into a prime (77861988851551) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 690877171 + ... + 690989861.

It is an arithmetic number, because the mean of its divisors is an integer number (562276170540).

Almost surely, 2^{77861988851556} 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 77861988851556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121451652836640).

77861988851556 is an abundant number, since it is smaller than the sum of its proper divisors (165041316821724).

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

77861988851556 is a wasteful number, since it uses less digits than its factorization.

77861988851556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113164 (or 113142 counting only the distinct ones).

The product of its digits is 8128512000, while the sum is 84.

The spelling of 77861988851556 in words is "seventy-seven trillion, eight hundred sixty-one billion, nine hundred eighty-eight million, eight hundred fifty-one thousand, five hundred fifty-six".