1661345 has 12 divisors (see below), whose sum is σ = 2319444. Its totient is φ = 1139040.

The previous prime is 1661333. The next prime is 1661347. The reversal of 1661345 is 5431661.

It can be written as a sum of positive squares in 2 ways, for example, as 659344 + 1002001 = 812^2 + 1001^2 .

It is not a de Polignac number, because 1661345 - 2⁶ = 1661281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661347) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3146 + ... + 3635.

It is an arithmetic number, because the mean of its divisors is an integer number (193287).

2^1661345 is an apocalyptic number.

It is an amenable number.

1661345 is a deficient number, since it is larger than the sum of its proper divisors (658099).

1661345 is an equidigital number, since it uses as much as digits as its factorization.

1661345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6800 (or 6793 counting only the distinct ones).

The product of its digits is 2160, while the sum is 26.

The square root of 1661345 is about 1288.9317282153. The cubic root of 1661345 is about 118.4367849317.

The spelling of 1661345 in words is "one million, six hundred sixty-one thousand, three hundred forty-five".