81344880 has 60 divisors (see below), whose sum is σ = 273185640. Its totient is φ = 21691776.

The previous prime is 81344873. The next prime is 81344891. The reversal of 81344880 is 8844318.

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

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 11 ways as a sum of consecutive naturals, for example, 55770 + ... + 57209.

It is an arithmetic number, because the mean of its divisors is an integer number (4553094).

Almost surely, 2^81344880 is an apocalyptic number.

81344880 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81344880 is an abundant number, since it is smaller than the sum of its proper divisors (191840760).

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

81344880 is a wasteful number, since it uses less digits than its factorization.

81344880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112998 (or 112989 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 36.

The square root of 81344880 is about 9019.1396485474. The cubic root of 81344880 is about 433.2880794294.

The spelling of 81344880 in words is "eighty-one million, three hundred forty-four thousand, eight hundred eighty".