81171790 has 16 divisors (see below), whose sum is σ = 166982112. Its totient is φ = 27830304.

The previous prime is 81171767. The next prime is 81171791. The reversal of 81171790 is 9717118.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81171791) 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, 579729 + ... + 579868.

It is an arithmetic number, because the mean of its divisors is an integer number (10436382).

Almost surely, 2^81171790 is an apocalyptic number.

81171790 is an abundant number, since it is smaller than the sum of its proper divisors (85810322).

81171790 is a wasteful number, since it uses less digits than its factorization.

81171790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1159611.

The product of its (nonzero) digits is 3528, while the sum is 34.

The square root of 81171790 is about 9009.5388339249. The cubic root of 81171790 is about 432.9805366500.

The spelling of 81171790 in words is "eighty-one million, one hundred seventy-one thousand, seven hundred ninety".