81516661518 has 32 divisors (see below), whose sum is σ = 167489640864. Its totient is φ = 26429939712.

The previous prime is 81516661517. The next prime is 81516661543.

81516661518 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×81516661518² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81516661517) 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 in 15 ways as a sum of consecutive naturals, for example, 714346 + ... + 820562.

It is an arithmetic number, because the mean of its divisors is an integer number (5234051277).

Almost surely, 2^81516661518 is an apocalyptic number.

81516661518 is an abundant number, since it is smaller than the sum of its proper divisors (85972979346).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81516661518 is a wasteful number, since it uses less digits than its factorization.

81516661518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109716.

The product of its digits is 345600, while the sum is 48.

The spelling of 81516661518 in words is "eighty-one billion, five hundred sixteen million, six hundred sixty-one thousand, five hundred eighteen".