81800210 has 32 divisors (see below), whose sum is σ = 151165440. Its totient is φ = 31855552.

The previous prime is 81800119. The next prime is 81800221. The reversal of 81800210 is 1200818.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 126107 + ... + 126753.

It is an arithmetic number, because the mean of its divisors is an integer number (4723920).

Almost surely, 2^81800210 is an apocalyptic number.

81800210 is a deficient number, since it is larger than the sum of its proper divisors (69365230).

81800210 is a wasteful number, since it uses less digits than its factorization.

81800210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 970.

The product of its (nonzero) digits is 128, while the sum is 20.

The square root of 81800210 is about 9044.3468531453. The cubic root of 81800210 is about 434.0950226220.

The spelling of 81800210 in words is "eighty-one million, eight hundred thousand, two hundred ten".