1661417161 has 2 divisors, whose sum is σ = 1661417162. Its totient is φ = 1661417160.

The previous prime is 1661417159. The next prime is 1661417183. The reversal of 1661417161 is 1617141661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1120575625 + 540841536 = 33475^2 + 23256^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661417161 - 2¹ = 1661417159 is a prime.

Together with 1661417159, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1661487161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830708580 + 830708581.

It is an arithmetic number, because the mean of its divisors is an integer number (830708581).

Almost surely, 2^1661417161 is an apocalyptic number.

It is an amenable number.

1661417161 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661417161 is an equidigital number, since it uses as much as digits as its factorization.

1661417161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6048, while the sum is 34.

The square root of 1661417161 is about 40760.4852890640. The cubic root of 1661417161 is about 1184.3849968557.

The spelling of 1661417161 in words is "one billion, six hundred sixty-one million, four hundred seventeen thousand, one hundred sixty-one".