81998485 has 8 divisors (see below), whose sum is σ = 98645976. Its totient is φ = 65433600.

The previous prime is 81998479. The next prime is 81998489. The reversal of 81998485 is 58489918.

It can be written as a sum of positive squares in 4 ways, for example, as 48566961 + 33431524 = 6969^2 + 5782^2 .

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

It is not a de Polignac number, because 81998485 - 2⁵ = 81998453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81998489) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 18444 + ... + 22453.

It is an arithmetic number, because the mean of its divisors is an integer number (12330747).

Almost surely, 2^81998485 is an apocalyptic number.

It is an amenable number.

81998485 is a deficient number, since it is larger than the sum of its proper divisors (16647491).

81998485 is a wasteful number, since it uses less digits than its factorization.

81998485 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41303.

The product of its digits is 829440, while the sum is 52.

The square root of 81998485 is about 9055.3014858700. The cubic root of 81998485 is about 434.4454729956.

The spelling of 81998485 in words is "eighty-one million, nine hundred ninety-eight thousand, four hundred eighty-five".