81764218 has 8 divisors (see below), whose sum is σ = 127978848. Its totient is φ = 39104604.

The previous prime is 81764171. The next prime is 81764261. The reversal of 81764218 is 81246718.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 888696 + ... + 888787.

It is an arithmetic number, because the mean of its divisors is an integer number (15997356).

Almost surely, 2^81764218 is an apocalyptic number.

81764218 is a deficient number, since it is larger than the sum of its proper divisors (46214630).

81764218 is a wasteful number, since it uses less digits than its factorization.

81764218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1777508.

The product of its digits is 21504, while the sum is 37.

The square root of 81764218 is about 9042.3568830256. The cubic root of 81764218 is about 434.0313461754.

The spelling of 81764218 in words is "eighty-one million, seven hundred sixty-four thousand, two hundred eighteen".