81997238 has 8 divisors (see below), whose sum is σ = 123034800. Its totient is φ = 40985640.

The previous prime is 81997211. The next prime is 81997241. The reversal of 81997238 is 83279918.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81997192 and 81997201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7088 + ... + 14636.

It is an arithmetic number, because the mean of its divisors is an integer number (15379350).

Almost surely, 2^81997238 is an apocalyptic number.

81997238 is a deficient number, since it is larger than the sum of its proper divisors (41037562).

81997238 is a wasteful number, since it uses less digits than its factorization.

81997238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12982.

The product of its digits is 217728, while the sum is 47.

The square root of 81997238 is about 9055.2326309157. The cubic root of 81997238 is about 434.4432706937.

The spelling of 81997238 in words is "eighty-one million, nine hundred ninety-seven thousand, two hundred thirty-eight".