993921 has 4 divisors (see below), whose sum is σ = 1325232. Its totient is φ = 662612.

The previous prime is 993919. The next prime is 993943. The reversal of 993921 is 129399.

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: 129399 = 3 ⋅43133.

It is a cyclic number.

It is not a de Polignac number, because 993921 - 2¹ = 993919 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (993961) 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, 165651 + ... + 165656.

It is an arithmetic number, because the mean of its divisors is an integer number (331308).

2⁹⁹³⁹²¹ is an apocalyptic number.

It is an amenable number.

993921 is a deficient number, since it is larger than the sum of its proper divisors (331311).

993921 is a wasteful number, since it uses less digits than its factorization.

993921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331310.

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

The square root of 993921 is about 996.9558666260. The cubic root of 993921 is about 99.7969546716.

The spelling of 993921 in words is "nine hundred ninety-three thousand, nine hundred twenty-one".