81018556386768 has 2560 divisors, whose sum is σ = 340654463385600. Its totient is φ = 17755220736000.

The previous prime is 81018556386709. The next prime is 81018556386797. The reversal of 81018556386768 is 86768365581018.

81018556386768 is a `hidden beast` number, since 8 + 1 + 0 + 1 + 8 + 556 + 3 + 8 + 6 + 7 + 68 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 81018556386696 and 81018556386705.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 511 ways as a sum of consecutive naturals, for example, 244769052363 + ... + 244769052693.

It is an arithmetic number, because the mean of its divisors is an integer number (133068149760).

Almost surely, 2^{81018556386768} is an apocalyptic number.

81018556386768 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81018556386768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (170327231692800).

81018556386768 is an abundant number, since it is smaller than the sum of its proper divisors (259635906998832).

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

81018556386768 is a wasteful number, since it uses less digits than its factorization.

81018556386768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491 (or 417 counting only the distinct ones).

The product of its (nonzero) digits is 464486400, while the sum is 72.

The spelling of 81018556386768 in words is "eighty-one trillion, eighteen billion, five hundred fifty-six million, three hundred eighty-six thousand, seven hundred sixty-eight".