81336289 has 4 divisors (see below), whose sum is σ = 81355456. Its totient is φ = 81317124.

The previous prime is 81336287. The next prime is 81336317. The reversal of 81336289 is 98263318.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 98263318 = 2 ⋅49131659.

It is a cyclic number.

It is not a de Polignac number, because 81336289 - 2¹ = 81336287 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81336287) 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, 69 + ... + 12754.

It is an arithmetic number, because the mean of its divisors is an integer number (20338864).

Almost surely, 2^81336289 is an apocalyptic number.

It is an amenable number.

81336289 is a deficient number, since it is larger than the sum of its proper divisors (19167).

81336289 is a wasteful number, since it uses less digits than its factorization.

81336289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19166.

The product of its digits is 62208, while the sum is 40.

The square root of 81336289 is about 9018.6633710323. The cubic root of 81336289 is about 433.2728254108.

The spelling of 81336289 in words is "eighty-one million, three hundred thirty-six thousand, two hundred eighty-nine".