81488747 has 6 divisors (see below), whose sum is σ = 85186332. Its totient is φ = 77945252.

The previous prime is 81488731. The next prime is 81488749. The reversal of 81488747 is 74788418.

It is not a de Polignac number, because 81488747 - 2⁴ = 81488731 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81488749) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 76493 + ... + 77550.

It is an arithmetic number, because the mean of its divisors is an integer number (14197722).

Almost surely, 2^81488747 is an apocalyptic number.

81488747 is a deficient number, since it is larger than the sum of its proper divisors (3697585).

81488747 is a wasteful number, since it uses less digits than its factorization.

81488747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154089 (or 154066 counting only the distinct ones).

The product of its digits is 401408, while the sum is 47.

The square root of 81488747 is about 9027.1117750917. Note that the first 3 decimals coincide. The cubic root of 81488747 is about 433.5433675434.

The spelling of 81488747 in words is "eighty-one million, four hundred eighty-eight thousand, seven hundred forty-seven".