81228653 has 16 divisors (see below), whose sum is σ = 91893120. Its totient is φ = 71150400.

The previous prime is 81228619. The next prime is 81228659. The reversal of 81228653 is 35682218.

It is a cyclic number.

It is not a de Polignac number, because 81228653 - 2²⁰ = 80180077 is a prime.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81228659) 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 15 ways as a sum of consecutive naturals, for example, 43448 + ... + 45278.

It is an arithmetic number, because the mean of its divisors is an integer number (5743320).

Almost surely, 2^81228653 is an apocalyptic number.

It is an amenable number.

81228653 is a deficient number, since it is larger than the sum of its proper divisors (10664467).

81228653 is a wasteful number, since it uses less digits than its factorization.

81228653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1988.

The product of its digits is 23040, while the sum is 35.

The square root of 81228653 is about 9012.6939923643. The cubic root of 81228653 is about 433.0816178482.

The spelling of 81228653 in words is "eighty-one million, two hundred twenty-eight thousand, six hundred fifty-three".