81845042 has 16 divisors (see below), whose sum is σ = 125604312. Its totient is φ = 39985920.

The previous prime is 81845041. The next prime is 81845051. The reversal of 81845042 is 24054818.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 30019441 + 51825601 = 5479^2 + 7199^2 .

It is a super-2 number, since 2×81845042² = 13397221799963528, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81845041) 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 7 ways as a sum of consecutive naturals, for example, 17018 + ... + 21290.

Almost surely, 2^81845042 is an apocalyptic number.

81845042 is a deficient number, since it is larger than the sum of its proper divisors (43759270).

81845042 is a wasteful number, since it uses less digits than its factorization.

81845042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4493.

The product of its (nonzero) digits is 10240, while the sum is 32.

The square root of 81845042 is about 9046.8249679100. The cubic root of 81845042 is about 434.1743125316.

The spelling of 81845042 in words is "eighty-one million, eight hundred forty-five thousand, forty-two".