1620218161 has 2 divisors, whose sum is σ = 1620218162. Its totient is φ = 1620218160.

The previous prime is 1620218129. The next prime is 1620218219. The reversal of 1620218161 is 1618120261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1153009936 + 467208225 = 33956^2 + 21615^2 .

It is an emirp because it is prime and its reverse (1618120261) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1620218161 - 2⁵ = 1620218129 is a prime.

It is not a weakly prime, because it can be changed into another prime (1620218861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810109080 + 810109081.

It is an arithmetic number, because the mean of its divisors is an integer number (810109081).

Almost surely, 2^1620218161 is an apocalyptic number.

It is an amenable number.

1620218161 is a deficient number, since it is larger than the sum of its proper divisors (1).

1620218161 is an equidigital number, since it uses as much as digits as its factorization.

1620218161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 1620218161 is about 40251.9336305723. The cubic root of 1620218161 is about 1174.5130104435.

The spelling of 1620218161 in words is "one billion, six hundred twenty million, two hundred eighteen thousand, one hundred sixty-one".