81988918 has 8 divisors (see below), whose sum is σ = 134163720. Its totient is φ = 37267680.

The previous prime is 81988897. The next prime is 81988931.

81988918 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1863363 + ... + 1863406.

It is an arithmetic number, because the mean of its divisors is an integer number (16770465).

Almost surely, 2^81988918 is an apocalyptic number.

81988918 is a deficient number, since it is larger than the sum of its proper divisors (52174802).

81988918 is a wasteful number, since it uses less digits than its factorization.

81988918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3726782.

The product of its digits is 331776, while the sum is 52.

The square root of 81988918 is about 9054.7732163760. The cubic root of 81988918 is about 434.4285763359.

The spelling of 81988918 in words is "eighty-one million, nine hundred eighty-eight thousand, nine hundred eighteen".