81318259 has 8 divisors (see below), whose sum is σ = 93929328. Its totient is φ = 69576960.

The previous prime is 81318257. The next prime is 81318269. The reversal of 81318259 is 95281318.

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

It is a cyclic number.

It is not a de Polignac number, because 81318259 - 2¹ = 81318257 is a prime.

It is a super-2 number, since 2×81318259² = 13225318493582162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81318257) 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, 217242 + ... + 217615.

It is an arithmetic number, because the mean of its divisors is an integer number (11741166).

Almost surely, 2^81318259 is an apocalyptic number.

81318259 is a deficient number, since it is larger than the sum of its proper divisors (12611069).

81318259 is a wasteful number, since it uses less digits than its factorization.

81318259 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 434885.

The product of its digits is 17280, while the sum is 37.

The square root of 81318259 is about 9017.6637218295. The cubic root of 81318259 is about 433.2408081876.

The spelling of 81318259 in words is "eighty-one million, three hundred eighteen thousand, two hundred fifty-nine".