993886921 has 4 divisors (see below), whose sum is σ = 996365844. Its totient is φ = 991408000.

The previous prime is 993886853. The next prime is 993886931. The reversal of 993886921 is 129688399.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 818589321 + 175297600 = 28611^2 + 13240^2 .

It is a cyclic number.

It is not a de Polignac number, because 993886921 - 2¹¹ = 993884873 is a prime.

It is a super-2 number, since 2×993886921² = 1975622423469720482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (993886931) 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, 1238860 + ... + 1239661.

It is an arithmetic number, because the mean of its divisors is an integer number (249091461).

Almost surely, 2^993886921 is an apocalyptic number.

It is an amenable number.

993886921 is a deficient number, since it is larger than the sum of its proper divisors (2478923).

993886921 is a wasteful number, since it uses less digits than its factorization.

993886921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2478922.

The product of its digits is 1679616, while the sum is 55.

The square root of 993886921 is about 31525.9721658191. The cubic root of 993886921 is about 997.9581406480.

The spelling of 993886921 in words is "nine hundred ninety-three million, eight hundred eighty-six thousand, nine hundred twenty-one".