1691161 has 2 divisors, whose sum is σ = 1691162. Its totient is φ = 1691160.

The previous prime is 1691141. The next prime is 1691189. The reversal of 1691161 is 1611961.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1625625 + 65536 = 1275^2 + 256^2 .

It is a cyclic number.

It is not a de Polignac number, because 1691161 - 2⁷ = 1691033 is a prime.

It is not a weakly prime, because it can be changed into another prime (1691101) 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, 845580 + 845581.

It is an arithmetic number, because the mean of its divisors is an integer number (845581).

2^1691161 is an apocalyptic number.

It is an amenable number.

1691161 is a deficient number, since it is larger than the sum of its proper divisors (1).

1691161 is an equidigital number, since it uses as much as digits as its factorization.

1691161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 324, while the sum is 25.

The square root of 1691161 is about 1300.4464617969. The cubic root of 1691161 is about 119.1411126410.

The spelling of 1691161 in words is "one million, six hundred ninety-one thousand, one hundred sixty-one".