1667518334221 has 2 divisors, whose sum is σ = 1667518334222. Its totient is φ = 1667518334220.

The previous prime is 1667518334173. The next prime is 1667518334227. The reversal of 1667518334221 is 1224338157661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1567539056196 + 99979278025 = 1252014^2 + 316195^2 .

It is an emirp because it is prime and its reverse (1224338157661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1667518334221 - 2¹⁵ = 1667518301453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1667518334227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833759167110 + 833759167111.

It is an arithmetic number, because the mean of its divisors is an integer number (833759167111).

Almost surely, 2^{1667518334221} is an apocalyptic number.

It is an amenable number.

1667518334221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1667518334221 is an equidigital number, since it uses as much as digits as its factorization.

1667518334221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1451520, while the sum is 49.

The spelling of 1667518334221 in words is "one trillion, six hundred sixty-seven billion, five hundred eighteen million, three hundred thirty-four thousand, two hundred twenty-one".