81947924186 has 16 divisors (see below), whose sum is σ = 124762809600. Its totient is φ = 40364398800.

The previous prime is 81947924183. The next prime is 81947924189. The reversal of 81947924186 is 68142974918.

It is an interprime number because it is at equal distance from previous prime (81947924183) and next prime (81947924189).

It is not an unprimeable number, because it can be changed into a prime (81947924183) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 979106 + ... + 1059501.

It is an arithmetic number, because the mean of its divisors is an integer number (7797675600).

Almost surely, 2^81947924186 is an apocalyptic number.

81947924186 is a deficient number, since it is larger than the sum of its proper divisors (42814885414).

81947924186 is a wasteful number, since it uses less digits than its factorization.

81947924186 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2038909.

The product of its digits is 6967296, while the sum is 59.

The spelling of 81947924186 in words is "eighty-one billion, nine hundred forty-seven million, nine hundred twenty-four thousand, one hundred eighty-six".