81398489 has 8 divisors (see below), whose sum is σ = 87773280. Its totient is φ = 75232800.

The previous prime is 81398477. The next prime is 81398503. The reversal of 81398489 is 98489318.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81398489 is a prime.

It is a super-2 number, since 2×81398489² = 13251428022966242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81398459) 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, 51467 + ... + 53024.

It is an arithmetic number, because the mean of its divisors is an integer number (10971660).

Almost surely, 2^81398489 is an apocalyptic number.

It is an amenable number.

81398489 is a deficient number, since it is larger than the sum of its proper divisors (6374791).

81398489 is a wasteful number, since it uses less digits than its factorization.

81398489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104551.

The product of its digits is 497664, while the sum is 50.

The square root of 81398489 is about 9022.1111165846. Note that the first 5 decimals coincide. The cubic root of 81398489 is about 433.3832423120.

The spelling of 81398489 in words is "eighty-one million, three hundred ninety-eight thousand, four hundred eighty-nine".