993905643 has 4 divisors (see below), whose sum is σ = 1325207528. Its totient is φ = 662603760.

The previous prime is 993905623. The next prime is 993905807. The reversal of 993905643 is 346509399.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 346509399 = 3 ⋅115503133.

It is not a de Polignac number, because 993905643 - 2⁸ = 993905387 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 993905592 and 993905601.

It is not an unprimeable number, because it can be changed into a prime (993905623) 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, 165650938 + ... + 165650943.

It is an arithmetic number, because the mean of its divisors is an integer number (331301882).

Almost surely, 2^993905643 is an apocalyptic number.

993905643 is a deficient number, since it is larger than the sum of its proper divisors (331301885).

993905643 is a wasteful number, since it uses less digits than its factorization.

993905643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331301884.

The product of its (nonzero) digits is 787320, while the sum is 48.

The square root of 993905643 is about 31526.2690942014. The cubic root of 993905643 is about 997.9644068387.

The spelling of 993905643 in words is "nine hundred ninety-three million, nine hundred five thousand, six hundred forty-three".