81513131986 has 16 divisors (see below), whose sum is σ = 143645519808. Its totient is φ = 34201314000.

The previous prime is 81513131983. The next prime is 81513132007. The reversal of 81513131986 is 68913131518.

It is not an unprimeable number, because it can be changed into a prime (81513131981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 142505190 + ... + 142505761.

It is an arithmetic number, because the mean of its divisors is an integer number (8977844988).

Almost surely, 2^81513131986 is an apocalyptic number.

81513131986 is a deficient number, since it is larger than the sum of its proper divisors (62132387822).

81513131986 is a wasteful number, since it uses less digits than its factorization.

81513131986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285010977.

The product of its digits is 155520, while the sum is 46.

The spelling of 81513131986 in words is "eighty-one billion, five hundred thirteen million, one hundred thirty-one thousand, nine hundred eighty-six".