81287188 has 12 divisors (see below), whose sum is σ = 143634400. Its totient is φ = 40248792.

The previous prime is 81287069. The next prime is 81287189. The reversal of 81287188 is 88178218.

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81287189) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98238 + ... + 99061.

Almost surely, 2^81287188 is an apocalyptic number.

It is an amenable number.

81287188 is a deficient number, since it is larger than the sum of its proper divisors (62347212).

81287188 is a wasteful number, since it uses less digits than its factorization.

81287188 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197406 (or 197404 counting only the distinct ones).

The product of its digits is 57344, while the sum is 43.

The square root of 81287188 is about 9015.9407717664. The cubic root of 81287188 is about 433.1856219758.

The spelling of 81287188 in words is "eighty-one million, two hundred eighty-seven thousand, one hundred eighty-eight".