81138695 has 16 divisors (see below), whose sum is σ = 106941600. Its totient is φ = 58608000.

The previous prime is 81138691. The next prime is 81138703. The reversal of 81138695 is 59683118.

It is not a de Polignac number, because 81138695 - 2² = 81138691 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81138691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3245 + ... + 13145.

It is an arithmetic number, because the mean of its divisors is an integer number (6683850).

Almost surely, 2^81138695 is an apocalyptic number.

81138695 is a deficient number, since it is larger than the sum of its proper divisors (25802905).

81138695 is a wasteful number, since it uses less digits than its factorization.

81138695 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10066.

The product of its digits is 51840, while the sum is 41.

The square root of 81138695 is about 9007.7019821928. The cubic root of 81138695 is about 432.9216843535.

The spelling of 81138695 in words is "eighty-one million, one hundred thirty-eight thousand, six hundred ninety-five".