1620161 has 2 divisors, whose sum is σ = 1620162. Its totient is φ = 1620160.

The previous prime is 1620133. The next prime is 1620209. The reversal of 1620161 is 1610261.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1311025 + 309136 = 1145^2 + 556^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1620161 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1620121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810080 + 810081.

It is an arithmetic number, because the mean of its divisors is an integer number (810081).

2^1620161 is an apocalyptic number.

It is an amenable number.

1620161 is a deficient number, since it is larger than the sum of its proper divisors (1).

1620161 is an equidigital number, since it uses as much as digits as its factorization.

1620161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 1620161 is about 1272.8554513377. The cubic root of 1620161 is about 117.4499198080.

The spelling of 1620161 in words is "one million, six hundred twenty thousand, one hundred sixty-one".