1690121 has 2 divisors, whose sum is σ = 1690122. Its totient is φ = 1690120.

The previous prime is 1690103. The next prime is 1690153. The reversal of 1690121 is 1210961.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1690000 + 121 = 1300^2 + 11^2 .

It is a cyclic number.

It is not a de Polignac number, because 1690121 - 2⁶ = 1690057 is a prime.

It is a Sophie Germain prime.

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1690093 and 1690102.

It is not a weakly prime, because it can be changed into another prime (1690421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 845060 + 845061.

It is an arithmetic number, because the mean of its divisors is an integer number (845061).

2^1690121 is an apocalyptic number.

It is an amenable number.

1690121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1690121 is an equidigital number, since it uses as much as digits as its factorization.

1690121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 20.

The square root of 1690121 is about 1300.0465376286. The cubic root of 1690121 is about 119.1166852082.

The spelling of 1690121 in words is "one million, six hundred ninety thousand, one hundred twenty-one".