81550555505518 has 16 divisors (see below), whose sum is σ = 133446556401840. Its totient is φ = 37068380752000.

The previous prime is 81550555505483. The next prime is 81550555505539.

81550555505518 is nontrivially palindromic in base 10.

81550555505518 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15690588 + ... + 20231056.

It is an arithmetic number, because the mean of its divisors is an integer number (8340409775115).

Almost surely, 2^{81550555505518} is an apocalyptic number.

81550555505518 is a deficient number, since it is larger than the sum of its proper divisors (51896000896322).

81550555505518 is a wasteful number, since it uses less digits than its factorization.

81550555505518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5356883.

The product of its (nonzero) digits is 25000000, while the sum is 58.

The spelling of 81550555505518 in words is "eighty-one trillion, five hundred fifty billion, five hundred fifty-five million, five hundred five thousand, five hundred eighteen".