320185645581 has 4 divisors (see below), whose sum is σ = 426914194112. Its totient is φ = 213457097052.

The previous prime is 320185645519. The next prime is 320185645601. The reversal of 320185645581 is 185546581023.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 320185645581 - 2¹⁸ = 320185383437 is a prime.

It is a super-2 number, since 2×320185645581² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 320185645581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (320185645511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53364274261 + ... + 53364274266.

It is an arithmetic number, because the mean of its divisors is an integer number (106728548528).

Almost surely, 2^320185645581 is an apocalyptic number.

It is an amenable number.

320185645581 is a deficient number, since it is larger than the sum of its proper divisors (106728548531).

320185645581 is a wasteful number, since it uses less digits than its factorization.

320185645581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106728548530.

The product of its (nonzero) digits is 1152000, while the sum is 48.

The spelling of 320185645581 in words is "three hundred twenty billion, one hundred eighty-five million, six hundred forty-five thousand, five hundred eighty-one".