1665998 has 8 divisors (see below), whose sum is σ = 2508408. Its totient is φ = 829864.

The previous prime is 1665997. The next prime is 1666003. The reversal of 1665998 is 8995661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 836 + ... + 2007.

It is an arithmetic number, because the mean of its divisors is an integer number (313551).

2^1665998 is an apocalyptic number.

1665998 is a deficient number, since it is larger than the sum of its proper divisors (842410).

1665998 is a wasteful number, since it uses less digits than its factorization.

1665998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3138.

The product of its digits is 116640, while the sum is 44.

The square root of 1665998 is about 1290.7354492691. The cubic root of 1665998 is about 118.5472521888.

The spelling of 1665998 in words is "one million, six hundred sixty-five thousand, nine hundred ninety-eight".