81205344 has 72 divisors (see below), whose sum is σ = 251930952. Its totient is φ = 24606720.

The previous prime is 81205321. The next prime is 81205361. The reversal of 81205344 is 44350218.

81205344 is a `hidden beast` number, since 8 + 120 + 534 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9649 + ... + 15984.

It is an arithmetic number, because the mean of its divisors is an integer number (3499041).

Almost surely, 2^81205344 is an apocalyptic number.

It is an amenable number.

81205344 is an abundant number, since it is smaller than the sum of its proper divisors (170725608).

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

81205344 is a wasteful number, since it uses less digits than its factorization.

81205344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25660 (or 25649 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 81205344 is about 9011.4007790132. The cubic root of 81205344 is about 433.0401888499.

The spelling of 81205344 in words is "eighty-one million, two hundred five thousand, three hundred forty-four".