320978643 has 4 divisors (see below), whose sum is σ = 427971528. Its totient is φ = 213985760.

The previous prime is 320978599. The next prime is 320978711. The reversal of 320978643 is 346879023.

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

It is a cyclic number.

It is not a de Polignac number, because 320978643 - 2⁸ = 320978387 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 320978595 and 320978604.

It is not an unprimeable number, because it can be changed into a prime (320978243) 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, 53496438 + ... + 53496443.

It is an arithmetic number, because the mean of its divisors is an integer number (106992882).

Almost surely, 2^320978643 is an apocalyptic number.

320978643 is a deficient number, since it is larger than the sum of its proper divisors (106992885).

320978643 is a wasteful number, since it uses less digits than its factorization.

320978643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106992884.

The product of its (nonzero) digits is 217728, while the sum is 42.

The square root of 320978643 is about 17915.8768415057. The cubic root of 320978643 is about 684.6869423910.

The spelling of 320978643 in words is "three hundred twenty million, nine hundred seventy-eight thousand, six hundred forty-three".