1661173 has 2 divisors, whose sum is σ = 1661174. Its totient is φ = 1661172.

The previous prime is 1661161. The next prime is 1661237. The reversal of 1661173 is 3711661.

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., 1633284 + 27889 = 1278^2 + 167^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661173 - 2⁵ = 1661141 is a prime.

1661173 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1661123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830586 + 830587.

It is an arithmetic number, because the mean of its divisors is an integer number (830587).

2^1661173 is an apocalyptic number.

It is an amenable number.

1661173 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661173 is an equidigital number, since it uses as much as digits as its factorization.

1661173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 756, while the sum is 25.

The square root of 1661173 is about 1288.8650045680. The cubic root of 1661173 is about 118.4326975146.

The spelling of 1661173 in words is "one million, six hundred sixty-one thousand, one hundred seventy-three".