993388962721 has 3 divisors (see below), whose sum is σ = 993389959411. Its totient is φ = 993387966032.

The previous prime is 993388962697. The next prime is 993388962733. The reversal of 993388962721 is 127269883399.

The square root of 993388962721 is 996689.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 127269883399 = 71 ⋅1792533569.

It can be written as a sum of positive squares in only one way, i.e., 425415713121 + 567973249600 = 652239^2 + 753640^2 .

It is not a de Polignac number, because 993388962721 - 2⁵ = 993388962689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (993388966721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 498345 + ... + 1495033.

Almost surely, 2^993388962721 is an apocalyptic number.

993388962721 is the 996689-th square number.

993388962721 is the 498345-th centered octagonal number.

It is an amenable number.

993388962721 is a deficient number, since it is larger than the sum of its proper divisors (996690).

993388962721 is an frugal number, since it uses more digits than its factorization.

993388962721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1993378 (or 996689 counting only the distinct ones).

The product of its digits is 70543872, while the sum is 67.

The spelling of 993388962721 in words is "nine hundred ninety-three billion, three hundred eighty-eight million, nine hundred sixty-two thousand, seven hundred twenty-one".