81731822 has 8 divisors (see below), whose sum is σ = 124277376. Its totient is φ = 40306032.

The previous prime is 81731821. The next prime is 81731827. The reversal of 81731822 is 22813718.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81731821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 279758 + ... + 280049.

It is an arithmetic number, because the mean of its divisors is an integer number (15534672).

Almost surely, 2^81731822 is an apocalyptic number.

81731822 is a deficient number, since it is larger than the sum of its proper divisors (42545554).

81731822 is a wasteful number, since it uses less digits than its factorization.

81731822 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 559882.

The product of its digits is 5376, while the sum is 32.

The square root of 81731822 is about 9040.5653584275. The cubic root of 81731822 is about 433.9740157307.

The spelling of 81731822 in words is "eighty-one million, seven hundred thirty-one thousand, eight hundred twenty-two".