320121178875581 has 2 divisors, whose sum is σ = 320121178875582. Its totient is φ = 320121178875580.

The previous prime is 320121178875577. The next prime is 320121178875587. The reversal of 320121178875581 is 185578871121023.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 165415867188100 + 154705311687481 = 12861410^2 + 12438059^2 .

It is an emirp because it is prime and its reverse (185578871121023) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 320121178875581 - 2² = 320121178875577 is a prime.

It is a super-2 number, since 2×320121178875581² (a number of 30 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 320121178875581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (320121178875587) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160060589437790 + 160060589437791.

It is an arithmetic number, because the mean of its divisors is an integer number (160060589437791).

Almost surely, 2^{320121178875581} is an apocalyptic number.

It is an amenable number.

320121178875581 is a deficient number, since it is larger than the sum of its proper divisors (1).

320121178875581 is an equidigital number, since it uses as much as digits as its factorization.

320121178875581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7526400, while the sum is 59.

The spelling of 320121178875581 in words is "three hundred twenty trillion, one hundred twenty-one billion, one hundred seventy-eight million, eight hundred seventy-five thousand, five hundred eighty-one".