81220338 has 12 divisors (see below), whose sum is σ = 175977438. Its totient is φ = 27073440.

The previous prime is 81220319. The next prime is 81220343. The reversal of 81220338 is 83302218.

It can be written as a sum of positive squares in only one way, i.e., 53626329 + 27594009 = 7323^2 + 5253^2 .

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2256103 + ... + 2256138.

Almost surely, 2^81220338 is an apocalyptic number.

81220338 is an abundant number, since it is smaller than the sum of its proper divisors (94757100).

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

81220338 is a wasteful number, since it uses less digits than its factorization.

81220338 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4512249 (or 4512246 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 81220338 is about 9012.2326867431. The cubic root of 81220338 is about 433.0668398259.

The spelling of 81220338 in words is "eighty-one million, two hundred twenty thousand, three hundred thirty-eight".