81204240218 has 4 divisors (see below), whose sum is σ = 121806360330. Its totient is φ = 40602120108.

The previous prime is 81204240217. The next prime is 81204240283.

81204240218 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 66335608249 + 14868631969 = 257557^2 + 121937^2 .

It is not an unprimeable number, because it can be changed into a prime (81204240217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20301060053 + ... + 20301060056.

Almost surely, 2^81204240218 is an apocalyptic number.

81204240218 is a deficient number, since it is larger than the sum of its proper divisors (40602120112).

81204240218 is a wasteful number, since it uses less digits than its factorization.

81204240218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40602120111.

The product of its (nonzero) digits is 8192, while the sum is 32.

The spelling of 81204240218 in words is "eighty-one billion, two hundred four million, two hundred forty thousand, two hundred eighteen".