81250005218 has 8 divisors (see below), whose sum is σ = 122017221612. Its totient is φ = 40577598016.

The previous prime is 81250005217. The next prime is 81250005233.

It is a happy number.

81250005218 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 2 ways, for example, as 80138249569 + 1111755649 = 283087^2 + 33343^2 .

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81250005211) 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 3 ways as a sum of consecutive naturals, for example, 23700155 + ... + 23703582.

Almost surely, 2^81250005218 is an apocalyptic number.

81250005218 is a deficient number, since it is larger than the sum of its proper divisors (40767216394).

81250005218 is a wasteful number, since it uses less digits than its factorization.

81250005218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47404596.

The product of its (nonzero) digits is 6400, while the sum is 32.

The spelling of 81250005218 in words is "eighty-one billion, two hundred fifty million, five thousand, two hundred eighteen".