81479744 has 14 divisors (see below), whose sum is σ = 161686494. Its totient is φ = 40739840.

The previous prime is 81479743. The next prime is 81479747. The reversal of 81479744 is 44797418.

It can be written as a sum of positive squares in only one way, i.e., 69089344 + 12390400 = 8312^2 + 3520^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81479695 and 81479704.

It is not an unprimeable number, because it can be changed into a prime (81479743) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 636497 + ... + 636624.

Almost surely, 2^81479744 is an apocalyptic number.

It is an amenable number.

81479744 is a deficient number, since it is larger than the sum of its proper divisors (80206750).

81479744 is a wasteful number, since it uses less digits than its factorization.

81479744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1273133 (or 1273123 counting only the distinct ones).

The product of its digits is 225792, while the sum is 44.

The square root of 81479744 is about 9026.6130968376. The cubic root of 81479744 is about 433.5274007798.

The spelling of 81479744 in words is "eighty-one million, four hundred seventy-nine thousand, seven hundred forty-four".