81771781920192 has 168 divisors, whose sum is σ = 288472675292256. Its totient is φ = 21566184228864.

The previous prime is 81771781920167. The next prime is 81771781920197. The reversal of 81771781920192 is 29102918717718.

81771781920192 is a `hidden beast` number, since 8 + 177 + 178 + 1 + 9 + 201 + 92 = 666.

It is a tau number, because it is divible by the number of its divisors (168).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81771781920197) 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, 779974503 + ... + 780079334.

It is an arithmetic number, because the mean of its divisors is an integer number (1717099257692).

Almost surely, 2^{81771781920192} is an apocalyptic number.

It is an amenable number.

81771781920192 is an abundant number, since it is smaller than the sum of its proper divisors (206700893372064).

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

81771781920192 is a wasteful number, since it uses less digits than its factorization.

81771781920192 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1560053875 (or 1560053862 counting only the distinct ones).

The product of its (nonzero) digits is 7112448, while the sum is 63.

The spelling of 81771781920192 in words is "eighty-one trillion, seven hundred seventy-one billion, seven hundred eighty-one million, nine hundred twenty thousand, one hundred ninety-two".