81807938 has 16 divisors (see below), whose sum is σ = 126904320. Its totient is φ = 39529776.

The previous prime is 81807937. The next prime is 81807953. The reversal of 81807938 is 83970818.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81807937) 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, 1343 + ... + 12861.

It is an arithmetic number, because the mean of its divisors is an integer number (7931520).

Almost surely, 2^81807938 is an apocalyptic number.

81807938 is a deficient number, since it is larger than the sum of its proper divisors (45096382).

81807938 is a wasteful number, since it uses less digits than its factorization.

81807938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11641.

The product of its (nonzero) digits is 96768, while the sum is 44.

The square root of 81807938 is about 9044.7740712524. The cubic root of 81807938 is about 434.1086924349.

The spelling of 81807938 in words is "eighty-one million, eight hundred seven thousand, nine hundred thirty-eight".