81323887 has 4 divisors (see below), whose sum is σ = 82129176. Its totient is φ = 80518600.

The previous prime is 81323873. The next prime is 81323899. The reversal of 81323887 is 78832318.

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 81323887 - 2¹¹ = 81321839 is a prime.

It is a super-2 number, since 2×81323887² = 13227149193577538, 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 (81323807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 402493 + ... + 402694.

It is an arithmetic number, because the mean of its divisors is an integer number (20532294).

Almost surely, 2^81323887 is an apocalyptic number.

81323887 is a deficient number, since it is larger than the sum of its proper divisors (805289).

81323887 is a wasteful number, since it uses less digits than its factorization.

81323887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 805288.

The product of its digits is 64512, while the sum is 40.

The square root of 81323887 is about 9017.9757706483. The cubic root of 81323887 is about 433.2508027573.

The spelling of 81323887 in words is "eighty-one million, three hundred twenty-three thousand, eight hundred eighty-seven".