81828321 has 8 divisors (see below), whose sum is σ = 109146240. Its totient is φ = 54531312.

The previous prime is 81828317. The next prime is 81828347. The reversal of 81828321 is 12382818.

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

It is not a de Polignac number, because 81828321 - 2² = 81828317 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (81828301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12411 + ... + 17823.

It is an arithmetic number, because the mean of its divisors is an integer number (13643280).

Almost surely, 2^81828321 is an apocalyptic number.

It is an amenable number.

81828321 is a deficient number, since it is larger than the sum of its proper divisors (27317919).

81828321 is a wasteful number, since it uses less digits than its factorization.

81828321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10455.

The product of its digits is 6144, while the sum is 33.

The square root of 81828321 is about 9045.9007843332. The cubic root of 81828321 is about 434.1447431447.

The spelling of 81828321 in words is "eighty-one million, eight hundred twenty-eight thousand, three hundred twenty-one".