81228545 has 16 divisors (see below), whose sum is σ = 99645120. Its totient is φ = 63547584.

The previous prime is 81228541. The next prime is 81228559. The reversal of 81228545 is 54582218.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 81228545 - 2² = 81228541 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81228541) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 66359 + ... + 67571.

It is an arithmetic number, because the mean of its divisors is an integer number (6227820).

Almost surely, 2^81228545 is an apocalyptic number.

It is an amenable number.

81228545 is a deficient number, since it is larger than the sum of its proper divisors (18416575).

81228545 is a wasteful number, since it uses less digits than its factorization.

81228545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1504.

The product of its digits is 25600, while the sum is 35.

The square root of 81228545 is about 9012.6880008131. The cubic root of 81228545 is about 433.0814259092.

The spelling of 81228545 in words is "eighty-one million, two hundred twenty-eight thousand, five hundred forty-five".