1661369 has 4 divisors (see below), whose sum is σ = 1668240. Its totient is φ = 1654500.

The previous prime is 1661353. The next prime is 1661431. The reversal of 1661369 is 9631661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9631661 = 13 ⋅740897.

It is a cyclic number.

It is not a de Polignac number, because 1661369 - 2⁴ = 1661353 is a prime.

It is a super-2 number, since 2×1661369² = 5520293908322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661069) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3059 + ... + 3560.

It is an arithmetic number, because the mean of its divisors is an integer number (417060).

2^1661369 is an apocalyptic number.

It is an amenable number.

1661369 is a deficient number, since it is larger than the sum of its proper divisors (6871).

1661369 is an equidigital number, since it uses as much as digits as its factorization.

1661369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6870.

The product of its digits is 5832, while the sum is 32.

The square root of 1661369 is about 1288.9410382170. The cubic root of 1661369 is about 118.4373552466.

The spelling of 1661369 in words is "one million, six hundred sixty-one thousand, three hundred sixty-nine".