81411918 has 32 divisors (see below), whose sum is σ = 186353664. Its totient is φ = 23226912.

The previous prime is 81411907. The next prime is 81411971. The reversal of 81411918 is 81911418.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51171 + ... + 52737.

It is an arithmetic number, because the mean of its divisors is an integer number (5823552).

Almost surely, 2^81411918 is an apocalyptic number.

81411918 is an abundant number, since it is smaller than the sum of its proper divisors (104941746).

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

81411918 is a wasteful number, since it uses less digits than its factorization.

81411918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2816.

The product of its digits is 2304, while the sum is 33.

The square root of 81411918 is about 9022.8553130370. The cubic root of 81411918 is about 433.4070739728.

Subtracting 81411918 from its reverse (81911418), we obtain a triangular number (499500 = T₉₉₉).

The spelling of 81411918 in words is "eighty-one million, four hundred eleven thousand, nine hundred eighteen".