1667645 has 32 divisors (see below), whose sum is σ = 2488320. Its totient is φ = 1048320.

The previous prime is 1667641. The next prime is 1667647. The reversal of 1667645 is 5467661.

It is not a de Polignac number, because 1667645 - 2² = 1667641 is a prime.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1667641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 31439 + ... + 31491.

It is an arithmetic number, because the mean of its divisors is an integer number (77760).

2^1667645 is an apocalyptic number.

It is an amenable number.

1667645 is a deficient number, since it is larger than the sum of its proper divisors (820675).

1667645 is a wasteful number, since it uses less digits than its factorization.

1667645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125.

The product of its digits is 30240, while the sum is 35.

The square root of 1667645 is about 1291.3733000182. The cubic root of 1667645 is about 118.5863044605.

The spelling of 1667645 in words is "one million, six hundred sixty-seven thousand, six hundred forty-five".