81142744 has 16 divisors (see below), whose sum is σ = 152449200. Its totient is φ = 40489632.

The previous prime is 81142741. The next prime is 81142753. The reversal of 81142744 is 44724118.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81142741) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 5892 + ... + 14035.

It is an arithmetic number, because the mean of its divisors is an integer number (9528075).

Almost surely, 2^81142744 is an apocalyptic number.

It is an amenable number.

81142744 is a deficient number, since it is larger than the sum of its proper divisors (71306456).

81142744 is a wasteful number, since it uses less digits than its factorization.

81142744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20442 (or 20438 counting only the distinct ones).

The product of its digits is 7168, while the sum is 31.

The square root of 81142744 is about 9007.9267314960. The cubic root of 81142744 is about 432.9288854830.

The spelling of 81142744 in words is "eighty-one million, one hundred forty-two thousand, seven hundred forty-four".