81187886 has 16 divisors (see below), whose sum is σ = 138865104. Its totient is φ = 35266944.

The previous prime is 81187877. The next prime is 81187919. The reversal of 81187886 is 68878118.

It is a self number, because there is not a number n which added to its sum of digits gives 81187886.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 91400 + ... + 92283.

It is an arithmetic number, because the mean of its divisors is an integer number (8679069).

Almost surely, 2^81187886 is an apocalyptic number.

81187886 is a deficient number, since it is larger than the sum of its proper divisors (57677218).

81187886 is a wasteful number, since it uses less digits than its factorization.

81187886 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183715.

The product of its digits is 172032, while the sum is 47.

The square root of 81187886 is about 9010.4320651121. The cubic root of 81187886 is about 433.0091541213.

The spelling of 81187886 in words is "eighty-one million, one hundred eighty-seven thousand, eight hundred eighty-six".