81969159775 has 6 divisors (see below), whose sum is σ = 101641758152. Its totient is φ = 65575327800.

The previous prime is 81969159773. The next prime is 81969159817. The reversal of 81969159775 is 57795196918.

It is not a de Polignac number, because 81969159775 - 2¹ = 81969159773 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81969159775.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81969159773) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1639383171 + ... + 1639383220.

Almost surely, 2^81969159775 is an apocalyptic number.

81969159775 is a deficient number, since it is larger than the sum of its proper divisors (19672598377).

81969159775 is a wasteful number, since it uses less digits than its factorization.

81969159775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3278766401 (or 3278766396 counting only the distinct ones).

The product of its digits is 42865200, while the sum is 67.

The spelling of 81969159775 in words is "eighty-one billion, nine hundred sixty-nine million, one hundred fifty-nine thousand, seven hundred seventy-five".