999321 has 4 divisors (see below), whose sum is σ = 1332432. Its totient is φ = 666212.

The previous prime is 999307. The next prime is 999329. The reversal of 999321 is 123999.

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: 123999 = 3 ⋅41333.

It is a cyclic number.

It is not a de Polignac number, because 999321 - 2¹¹ = 997273 is a prime.

It is a super-2 number, since 2×999321² = 1997284922082, which contains 22 as substring.

It is a D-number.

It is a Curzon number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (999329) 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, 166551 + ... + 166556.

It is an arithmetic number, because the mean of its divisors is an integer number (333108).

2⁹⁹⁹³²¹ is an apocalyptic number.

It is an amenable number.

999321 is a deficient number, since it is larger than the sum of its proper divisors (333111).

999321 is a wasteful number, since it uses less digits than its factorization.

999321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333110.

The product of its digits is 4374, while the sum is 33.

The square root of 999321 is about 999.6604423503. The cubic root of 999321 is about 99.9773615421.

The spelling of 999321 in words is "nine hundred ninety-nine thousand, three hundred twenty-one".