81381255 has 16 divisors (see below), whose sum is σ = 131501664. Its totient is φ = 42972800.

The previous prime is 81381217. The next prime is 81381257. The reversal of 81381255 is 55218318.

It is a happy number.

It is not a de Polignac number, because 81381255 - 2¹³ = 81373063 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81381257) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25344 + ... + 28373.

It is an arithmetic number, because the mean of its divisors is an integer number (8218854).

Almost surely, 2^81381255 is an apocalyptic number.

81381255 is a deficient number, since it is larger than the sum of its proper divisors (50120409).

81381255 is a wasteful number, since it uses less digits than its factorization.

81381255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53826.

The product of its digits is 9600, while the sum is 33.

The square root of 81381255 is about 9021.1559680564. The cubic root of 81381255 is about 433.3526542996.

The spelling of 81381255 in words is "eighty-one million, three hundred eighty-one thousand, two hundred fifty-five".