81147744 has 60 divisors (see below), whose sum is σ = 238660884. Its totient is φ = 27048384.

The previous prime is 81147719. The next prime is 81147761. The reversal of 81147744 is 44774118.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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

It is a junction number, because it is equal to n+sod(n) for n = 81147699 and 81147708.

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 9 ways as a sum of consecutive naturals, for example, 13062 + ... + 18245.

Almost surely, 2^81147744 is an apocalyptic number.

It is an amenable number.

81147744 is an abundant number, since it is smaller than the sum of its proper divisors (157513140).

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

81147744 is a wasteful number, since it uses less digits than its factorization.

81147744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31329 (or 31312 counting only the distinct ones).

The product of its digits is 25088, while the sum is 36.

The square root of 81147744 is about 9008.2042605616. The cubic root of 81147744 is about 432.9377776314.

The spelling of 81147744 in words is "eighty-one million, one hundred forty-seven thousand, seven hundred forty-four".