321509957081 has 2 divisors, whose sum is σ = 321509957082. Its totient is φ = 321509957080.

The previous prime is 321509957059. The next prime is 321509957107. The reversal of 321509957081 is 180759905123.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 189450397081 + 132059560000 = 435259^2 + 363400^2 .

It is a cyclic number.

It is not a de Polignac number, because 321509957081 - 2¹⁸ = 321509694937 is a prime.

It is a super-2 number, since 2×321509957081² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (321509954081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160754978540 + 160754978541.

It is an arithmetic number, because the mean of its divisors is an integer number (160754978541).

Almost surely, 2^321509957081 is an apocalyptic number.

It is an amenable number.

321509957081 is a deficient number, since it is larger than the sum of its proper divisors (1).

321509957081 is an equidigital number, since it uses as much as digits as its factorization.

321509957081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 680400, while the sum is 50.

The spelling of 321509957081 in words is "three hundred twenty-one billion, five hundred nine million, nine hundred fifty-seven thousand, eighty-one".