321101981 has 2 divisors, whose sum is σ = 321101982. Its totient is φ = 321101980.

The previous prime is 321101969. The next prime is 321102031. The reversal of 321101981 is 189101123.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 229037956 + 92064025 = 15134^2 + 9595^2 .

It is an emirp because it is prime and its reverse (189101123) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 321101981 - 2¹⁰ = 321100957 is a prime.

It is a super-2 number, since 2×321101981² = 206212964404248722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 321101981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (321101951) 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 as a sum of consecutive naturals, namely, 160550990 + 160550991.

It is an arithmetic number, because the mean of its divisors is an integer number (160550991).

Almost surely, 2^321101981 is an apocalyptic number.

It is an amenable number.

321101981 is a deficient number, since it is larger than the sum of its proper divisors (1).

321101981 is an equidigital number, since it uses as much as digits as its factorization.

321101981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 26.

The square root of 321101981 is about 17919.3186533417. The cubic root of 321101981 is about 684.7746295375.

The spelling of 321101981 in words is "three hundred twenty-one million, one hundred one thousand, nine hundred eighty-one".