81785190 has 32 divisors (see below), whose sum is σ = 196636896. Its totient is φ = 21770240.

The previous prime is 81785167. The next prime is 81785203. The reversal of 81785190 is 9158718.

It is a super-2 number, since 2×81785190² = 13377634606672200, which contains 22 as substring.

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 in 15 ways as a sum of consecutive naturals, for example, 17104 + ... + 21356.

It is an arithmetic number, because the mean of its divisors is an integer number (6144903).

Almost surely, 2^81785190 is an apocalyptic number.

81785190 is an abundant number, since it is smaller than the sum of its proper divisors (114851706).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81785190 is a wasteful number, since it uses less digits than its factorization.

81785190 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4904.

The product of its (nonzero) digits is 20160, while the sum is 39.

The square root of 81785190 is about 9043.5164620849. The cubic root of 81785190 is about 434.0684517597.

The spelling of 81785190 in words is "eighty-one million, seven hundred eighty-five thousand, one hundred ninety".