81323287 has 4 divisors (see below), whose sum is σ = 85603480. Its totient is φ = 77043096.

The previous prime is 81323269. The next prime is 81323293. The reversal of 81323287 is 78232318.

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 81323287 - 2¹⁵ = 81290519 is a prime.

It is a super-2 number, since 2×81323287² = 13226954016968738, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81323587) 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, 2140068 + ... + 2140105.

It is an arithmetic number, because the mean of its divisors is an integer number (21400870).

Almost surely, 2^81323287 is an apocalyptic number.

81323287 is a deficient number, since it is larger than the sum of its proper divisors (4280193).

81323287 is a wasteful number, since it uses less digits than its factorization.

81323287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4280192.

The product of its digits is 16128, while the sum is 34.

The square root of 81323287 is about 9017.9425036978. The cubic root of 81323287 is about 433.2497372601.

The spelling of 81323287 in words is "eighty-one million, three hundred twenty-three thousand, two hundred eighty-seven".