81106321 has 4 divisors (see below), whose sum is σ = 81864432. Its totient is φ = 80348212.

The previous prime is 81106309. The next prime is 81106327. The reversal of 81106321 is 12360118.

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: 12360118 = 2 ⋅6180059.

It is a cyclic number.

It is not a de Polignac number, because 81106321 - 2⁹ = 81105809 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81106292 and 81106301.

It is not an unprimeable number, because it can be changed into a prime (81106327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 378895 + ... + 379108.

It is an arithmetic number, because the mean of its divisors is an integer number (20466108).

Almost surely, 2^81106321 is an apocalyptic number.

It is an amenable number.

81106321 is a deficient number, since it is larger than the sum of its proper divisors (758111).

81106321 is a wasteful number, since it uses less digits than its factorization.

81106321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 758110.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 81106321 is about 9005.9047851951. The cubic root of 81106321 is about 432.8640987135.

Adding to 81106321 its reverse (12360118), we get a palindrome (93466439).

The spelling of 81106321 in words is "eighty-one million, one hundred six thousand, three hundred twenty-one".