81187107 has 4 divisors (see below), whose sum is σ = 108249480. Its totient is φ = 54124736.

The previous prime is 81187097. The next prime is 81187111. The reversal of 81187107 is 70178118.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81187107 - 2⁴ = 81187091 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81187177) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13531182 + ... + 13531187.

It is an arithmetic number, because the mean of its divisors is an integer number (27062370).

Almost surely, 2^81187107 is an apocalyptic number.

81187107 is a deficient number, since it is larger than the sum of its proper divisors (27062373).

81187107 is a wasteful number, since it uses less digits than its factorization.

81187107 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27062372.

The product of its (nonzero) digits is 3136, while the sum is 33.

The square root of 81187107 is about 9010.3888373366. The cubic root of 81187107 is about 433.0077692053.

It can be divided in two parts, 8118 and 7107, that added together give a triangular number (15225 = T₁₇₄).

The spelling of 81187107 in words is "eighty-one million, one hundred eighty-seven thousand, one hundred seven".