81436259 has 4 divisors (see below), whose sum is σ = 81568440. Its totient is φ = 81304080.

The previous prime is 81436241. The next prime is 81436279. The reversal of 81436259 is 95263418.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81436259 - 2¹² = 81432163 is a prime.

It is a Duffinian number.

It is a plaindrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (81436279) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65162 + ... + 66399.

It is an arithmetic number, because the mean of its divisors is an integer number (20392110).

Almost surely, 2^81436259 is an apocalyptic number.

81436259 is a deficient number, since it is larger than the sum of its proper divisors (132181).

81436259 is a wasteful number, since it uses less digits than its factorization.

81436259 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132180.

The product of its digits is 51840, while the sum is 38.

The square root of 81436259 is about 9024.2040646253. The cubic root of 81436259 is about 433.4502638424.

It can be divided in two parts, 814 and 36259, that added together give a palindrome (37073).

The spelling of 81436259 in words is "eighty-one million, four hundred thirty-six thousand, two hundred fifty-nine".