81238845 has 16 divisors (see below), whose sum is σ = 131271552. Its totient is φ = 42897600.

The previous prime is 81238841. The next prime is 81238847. The reversal of 81238845 is 54883218.

It is not a de Polignac number, because 81238845 - 2² = 81238841 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81238841) 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, 25297 + ... + 28326.

It is an arithmetic number, because the mean of its divisors is an integer number (8204472).

Almost surely, 2^81238845 is an apocalyptic number.

It is an amenable number.

81238845 is a deficient number, since it is larger than the sum of its proper divisors (50032707).

81238845 is a wasteful number, since it uses less digits than its factorization.

81238845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53732.

The product of its digits is 61440, while the sum is 39.

The square root of 81238845 is about 9013.2593993516. The cubic root of 81238845 is about 433.0997304356.

The spelling of 81238845 in words is "eighty-one million, two hundred thirty-eight thousand, eight hundred forty-five".