81133730 has 16 divisors (see below), whose sum is σ = 146423160. Its totient is φ = 32368512.

The previous prime is 81133697. The next prime is 81133747. The reversal of 81133730 is 3733118.

It can be written as a sum of positive squares in 4 ways, for example, as 74666881 + 6466849 = 8641^2 + 2543^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81133730.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6539 + ... + 14318.

Almost surely, 2^81133730 is an apocalyptic number.

81133730 is a deficient number, since it is larger than the sum of its proper divisors (65289430).

81133730 is a wasteful number, since it uses less digits than its factorization.

81133730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21253.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 81133730 is about 9007.4263804929. The cubic root of 81133730 is about 432.9128537949.

Adding to 81133730 its reverse (3733118), we get a palindrome (84866848).

The spelling of 81133730 in words is "eighty-one million, one hundred thirty-three thousand, seven hundred thirty".