81013778055 has 24 divisors (see below), whose sum is σ = 160484437152. Its totient is φ = 37034869824.

The previous prime is 81013778051. The next prime is 81013778059. The reversal of 81013778055 is 55087731018.

It is an interprime number because it is at equal distance from previous prime (81013778051) and next prime (81013778059).

It is not a de Polignac number, because 81013778055 - 2² = 81013778051 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 81013778055.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81013778051) 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, 128592984 + ... + 128593613.

It is an arithmetic number, because the mean of its divisors is an integer number (6686851548).

Almost surely, 2^81013778055 is an apocalyptic number.

81013778055 is a deficient number, since it is larger than the sum of its proper divisors (79470659097).

81013778055 is a wasteful number, since it uses less digits than its factorization.

81013778055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257186615 (or 257186612 counting only the distinct ones).

The product of its (nonzero) digits is 235200, while the sum is 45.

The spelling of 81013778055 in words is "eighty-one billion, thirteen million, seven hundred seventy-eight thousand, fifty-five".