81170140 has 24 divisors (see below), whose sum is σ = 170891280. Its totient is φ = 32385408.

The previous prime is 81170129. The next prime is 81170143. The reversal of 81170140 is 4107118.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81170143) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3219 + ... + 13141.

It is an arithmetic number, because the mean of its divisors is an integer number (7120470).

Almost surely, 2^81170140 is an apocalyptic number.

It is an amenable number.

81170140 is an abundant number, since it is smaller than the sum of its proper divisors (89721140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81170140 is a wasteful number, since it uses less digits than its factorization.

81170140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10341 (or 10339 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 22.

The square root of 81170140 is about 9009.4472638448. The cubic root of 81170140 is about 432.9776028610.

Adding to 81170140 its reverse (4107118), we get a palindrome (85277258).

The spelling of 81170140 in words is "eighty-one million, one hundred seventy thousand, one hundred forty".