81457444 has 24 divisors (see below), whose sum is σ = 150131520. Its totient is φ = 38595744.

The previous prime is 81457393. The next prime is 81457463. The reversal of 81457444 is 44475418.

It is a happy 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, 5967 + ... + 14089.

It is an arithmetic number, because the mean of its divisors is an integer number (6255480).

Almost surely, 2^81457444 is an apocalyptic number.

It is an amenable number.

81457444 is a deficient number, since it is larger than the sum of its proper divisors (68674076).

81457444 is a wasteful number, since it uses less digits than its factorization.

81457444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8259 (or 8257 counting only the distinct ones).

The product of its digits is 71680, while the sum is 37.

The square root of 81457444 is about 9025.3777760269. The cubic root of 81457444 is about 433.4878468053.

The spelling of 81457444 in words is "eighty-one million, four hundred fifty-seven thousand, four hundred forty-four".