81228424 has 16 divisors (see below), whose sum is σ = 152585100. Its totient is φ = 40539072.

The previous prime is 81228373. The next prime is 81228443. The reversal of 81228424 is 42482218.

It can be written as a sum of positive squares in 2 ways, for example, as 79744900 + 1483524 = 8930^2 + 1218^2 .

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

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 3 ways as a sum of consecutive naturals, for example, 4659 + ... + 13570.

Almost surely, 2^81228424 is an apocalyptic number.

It is an amenable number.

81228424 is a deficient number, since it is larger than the sum of its proper divisors (71356676).

81228424 is a wasteful number, since it uses less digits than its factorization.

81228424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18792 (or 18788 counting only the distinct ones).

The product of its digits is 8192, while the sum is 31.

The square root of 81228424 is about 9012.6812880519. The cubic root of 81228424 is about 433.0812108662.

The spelling of 81228424 in words is "eighty-one million, two hundred twenty-eight thousand, four hundred twenty-four".