81812544 has 56 divisors (see below), whose sum is σ = 236146848. Its totient is φ = 24791040.

The previous prime is 81812501. The next prime is 81812557. The reversal of 81812544 is 44521818.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17257 + ... + 21480.

It is an arithmetic number, because the mean of its divisors is an integer number (4216908).

Almost surely, 2^81812544 is an apocalyptic number.

It is an amenable number.

81812544 is an abundant number, since it is smaller than the sum of its proper divisors (154334304).

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

81812544 is a wasteful number, since it uses less digits than its factorization.

81812544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38763 (or 38753 counting only the distinct ones).

The product of its digits is 10240, while the sum is 33.

The square root of 81812544 is about 9045.0286898384. The cubic root of 81812544 is about 434.1168394321.

The spelling of 81812544 in words is "eighty-one million, eight hundred twelve thousand, five hundred forty-four".