81364321 has 4 divisors (see below), whose sum is σ = 81395392. Its totient is φ = 81333252.

The previous prime is 81364313. The next prime is 81364337. The reversal of 81364321 is 12346318.

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.

It is a cyclic number.

It is not a de Polignac number, because 81364321 - 2³ = 81364313 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81364321.

It is not an unprimeable number, because it can be changed into a prime (81364351) 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, 11205 + ... + 16978.

It is an arithmetic number, because the mean of its divisors is an integer number (20348848).

Almost surely, 2^81364321 is an apocalyptic number.

It is an amenable number.

81364321 is a deficient number, since it is larger than the sum of its proper divisors (31071).

81364321 is a wasteful number, since it uses less digits than its factorization.

81364321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31070.

The product of its digits is 3456, while the sum is 28.

The square root of 81364321 is about 9020.2173477140. The cubic root of 81364321 is about 433.3225945399.

The spelling of 81364321 in words is "eighty-one million, three hundred sixty-four thousand, three hundred twenty-one".