1666398 has 32 divisors (see below), whose sum is σ = 3526560. Its totient is φ = 524160.

The previous prime is 1666397. The next prime is 1666403. The reversal of 1666398 is 8936661.

It is a happy number.

1666398 is an undulating number in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666393) 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 15 ways as a sum of consecutive naturals, for example, 10536 + ... + 10692.

It is an arithmetic number, because the mean of its divisors is an integer number (110205).

2^1666398 is an apocalyptic number.

1666398 is an abundant number, since it is smaller than the sum of its proper divisors (1860162).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1666398 is a wasteful number, since it uses less digits than its factorization.

1666398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252.

The product of its digits is 46656, while the sum is 39.

The square root of 1666398 is about 1290.8903903895. The cubic root of 1666398 is about 118.5567390162.

It can be divided in two parts, 16663 and 98, that added together give a palindrome (16761).

The spelling of 1666398 in words is "one million, six hundred sixty-six thousand, three hundred ninety-eight".