1661267 has 4 divisors (see below), whose sum is σ = 1733520. Its totient is φ = 1589016.

The previous prime is 1661251. The next prime is 1661273. The reversal of 1661267 is 7621661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1661267 - 2⁴ = 1661251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661237) 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 in 3 ways as a sum of consecutive naturals, for example, 36092 + ... + 36137.

It is an arithmetic number, because the mean of its divisors is an integer number (433380).

2^1661267 is an apocalyptic number.

1661267 is a deficient number, since it is larger than the sum of its proper divisors (72253).

1661267 is an equidigital number, since it uses as much as digits as its factorization.

1661267 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72252.

The product of its digits is 3024, while the sum is 29.

The square root of 1661267 is about 1288.9014702451. The cubic root of 1661267 is about 118.4349313706.

The spelling of 1661267 in words is "one million, six hundred sixty-one thousand, two hundred sixty-seven".