81005258 has 8 divisors (see below), whose sum is σ = 124471620. Its totient is φ = 39514720.

The previous prime is 81005251. The next prime is 81005269. The reversal of 81005258 is 85250018.

It can be written as a sum of positive squares in 2 ways, for example, as 79619929 + 1385329 = 8923^2 + 1177^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81005258.

It is not an unprimeable number, because it can be changed into a prime (81005251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 493853 + ... + 494016.

Almost surely, 2^81005258 is an apocalyptic number.

81005258 is a deficient number, since it is larger than the sum of its proper divisors (43466362).

81005258 is a wasteful number, since it uses less digits than its factorization.

81005258 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 987912.

The product of its (nonzero) digits is 3200, while the sum is 29.

The square root of 81005258 is about 9000.2921063708. The cubic root of 81005258 is about 432.6842330480.

The spelling of 81005258 in words is "eighty-one million, five thousand, two hundred fifty-eight".