1998644 has 6 divisors (see below), whose sum is σ = 3497634. Its totient is φ = 999320.

The previous prime is 1998643. The next prime is 1998679. The reversal of 1998644 is 4468991.

It can be written as a sum of positive squares in only one way, i.e., 1993744 + 4900 = 1412^2 + 70^2 .

It is a plaindrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 249827 + ... + 249834.

It is an arithmetic number, because the mean of its divisors is an integer number (582939).

2^1998644 is an apocalyptic number.

It is an amenable number.

1998644 is a deficient number, since it is larger than the sum of its proper divisors (1498990).

1998644 is a wasteful number, since it uses less digits than its factorization.

1998644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 499665 (or 499663 counting only the distinct ones).

The product of its digits is 62208, while the sum is 41.

The square root of 1998644 is about 1413.7340626865. The cubic root of 1998644 is about 125.9636243362.

The spelling of 1998644 in words is "one million, nine hundred ninety-eight thousand, six hundred forty-four".