81783028 has 36 divisors (see below), whose sum is σ = 150933132. Its totient is φ = 38737920.

The previous prime is 81783017. The next prime is 81783029. The reversal of 81783028 is 82038718.

It can be written as a sum of positive squares in 6 ways, for example, as 3849444 + 77933584 = 1962^2 + 8828^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81783029) 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 11 ways as a sum of consecutive naturals, for example, 843076 + ... + 843172.

It is an arithmetic number, because the mean of its divisors is an integer number (4192587).

Almost surely, 2^81783028 is an apocalyptic number.

It is an amenable number.

81783028 is a deficient number, since it is larger than the sum of its proper divisors (69150104).

81783028 is a wasteful number, since it uses less digits than its factorization.

81783028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292 (or 193 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 37.

The square root of 81783028 is about 9043.3969281460. The cubic root of 81783028 is about 434.0646268445.

It can be divided in two parts, 817 and 83028, that multiplied together give a palindrome (67833876).

The spelling of 81783028 in words is "eighty-one million, seven hundred eighty-three thousand, twenty-eight".