320991906 has 8 divisors (see below), whose sum is σ = 641983824. Its totient is φ = 106997300.

The previous prime is 320991899. The next prime is 320991907. The reversal of 320991906 is 609199023.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

320991906 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (320991907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26749320 + ... + 26749331.

It is an arithmetic number, because the mean of its divisors is an integer number (80247978).

Almost surely, 2^320991906 is an apocalyptic number.

320991906 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

320991906 is a wasteful number, since it uses less digits than its factorization.

320991906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53498656.

The product of its (nonzero) digits is 26244, while the sum is 39.

The square root of 320991906 is about 17916.2469842319. The cubic root of 320991906 is about 684.6963727981.

The spelling of 320991906 in words is "three hundred twenty million, nine hundred ninety-one thousand, nine hundred six".