81785422 has 4 divisors (see below), whose sum is σ = 122678136. Its totient is φ = 40892710.

The previous prime is 81785377. The next prime is 81785449. The reversal of 81785422 is 22458718.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20446354 + ... + 20446357.

It is an arithmetic number, because the mean of its divisors is an integer number (30669534).

Almost surely, 2^81785422 is an apocalyptic number.

81785422 is a deficient number, since it is larger than the sum of its proper divisors (40892714).

81785422 is a wasteful number, since it uses less digits than its factorization.

81785422 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40892713.

The product of its digits is 35840, while the sum is 37.

The square root of 81785422 is about 9043.5292889447. The cubic root of 81785422 is about 434.0688621999.

The spelling of 81785422 in words is "eighty-one million, seven hundred eighty-five thousand, four hundred twenty-two".