81481144 has 32 divisors (see below), whose sum is σ = 159315840. Its totient is φ = 39024000.

The previous prime is 81481133. The next prime is 81481151. The reversal of 81481144 is 44118418.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

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, 23422 + ... + 26674.

It is an arithmetic number, because the mean of its divisors is an integer number (4978620).

Almost surely, 2^81481144 is an apocalyptic number.

It is an amenable number.

81481144 is a deficient number, since it is larger than the sum of its proper divisors (77834696).

81481144 is a wasteful number, since it uses less digits than its factorization.

81481144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3391 (or 3387 counting only the distinct ones).

The product of its digits is 4096, while the sum is 31.

The square root of 81481144 is about 9026.6906449706. The cubic root of 81481144 is about 433.5298837482.

The spelling of 81481144 in words is "eighty-one million, four hundred eighty-one thousand, one hundred forty-four".