81820344 has 32 divisors (see below), whose sum is σ = 204819840. Its totient is φ = 27237600.

The previous prime is 81820313. The next prime is 81820367. The reversal of 81820344 is 44302818.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21549 + ... + 25059.

It is an arithmetic number, because the mean of its divisors is an integer number (6400620).

Almost surely, 2^81820344 is an apocalyptic number.

It is an amenable number.

81820344 is an abundant number, since it is smaller than the sum of its proper divisors (122999496).

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

81820344 is a wasteful number, since it uses less digits than its factorization.

81820344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4491 (or 4487 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 30.

The square root of 81820344 is about 9045.4598556403. The cubic root of 81820344 is about 434.1306352128.

The spelling of 81820344 in words is "eighty-one million, eight hundred twenty thousand, three hundred forty-four".